Ninja PREPi Review: I Tested It Against the #1 Food Processor

The Ninja PREPi performs like a full-size food processor, but it can also dice vegetables into uniform cubes five times faster than doing it by hand.

At least, that’s what Ninja wants you to believe.

Besides dicing, it can chop, slice, shred, purée, and even crinkle-cut your food. But can it actually compete with the best food processor on the market?

To find out, I tested the Ninja PREPi side by side against the Cuisinart 14-Cup, which was named the best overall food processor by both The New York Times Wirecutter and America’s Test Kitchen.

I chopped onions and carrots, sliced cucumbers and tomatoes, shredded carrots and cheese, made hummus, and tested Ninja’s special dicing and crinkle-cutting attachments. I compared how quickly each machine worked, how consistent the results were, and how easy everything was to use.

I also compared both machines against a chef’s knife and box grater to find out whether they actually save time once you factor in setup and cleanup.

In this review, I’ll break down how the Ninja PREPi performed in each test, how it compares to the Cuisinart and manual prep tools, and whether it’s worth buying.

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Use the links below to navigate this review:

• Chopping Test
• Purée Test
• Slicing Test
• Shredding Test
• Dicing Test
• Crinkle Cut Test
• Design and Ease of Use
• Bottom Line: Is the Ninja PREPi Worth Buying?

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Chopping Test

For the first test, I peeled and cut an onion into roughly 1-inch chunks before putting it in the food processors.

After just three pulses in the Ninja PREPi, the onion was chopped into small, relatively consistent pieces.

With the Cuisinart, several pieces were still too large after three pulses. So I gave it another pulse, and even then, the results were noticeably less consistent. Some pieces were chopped finely, while others were still pretty large.

With a chef’s knife, the pieces were much more uniform. But it took me about 1 minute and 45 seconds to prepare and dice the onion.

Next, I repeated the test with carrots. For each machine, I peeled three carrots and cut them into roughly 1-inch pieces before processing them.

After five pulses in the Ninja, most of the carrots were chopped into somewhat even pieces.

With the Cuisinart, I started with five pulses, but several large chunks were still left. So I gave it two more pulses, and even then, some pieces were still large while others were chopped into tiny bits.

Using the knife, it took about two minutes. The pieces were more evenly shaped, although they were also a little larger than what the food processors produced.

Here’s how the chopping tests compared:

Test	Ninja PREPi	Cuisinart	Chef’s Knife
Onion	3 pulses	4 pulses	1 min 45 sec
Carrots	5 pulses	7 pulses	About 2 min
Cut consistency	More even among processors	More uneven	Most controlled
Carrot prep and chopping, excluding peeling	About 50–60 sec	About 50–60 sec	About 2 min

One thing worth pointing out is that both machines chop food in seconds, but you still have to prepare the ingredients before putting them in.

For the onion test, peeling and cutting the onion into chunks took about a minute. Setting up either food processor and chopping took roughly another minute or less. Washing the machines afterward took approximately two minutes.

Washing my knife and cutting board took about 1 minute and 50 seconds.

So for a single onion, I’d probably just use a knife. But if I needed to chop ten onions, that’s a different story. The time saved during processing would start to add up.

One other small advantage of the Ninja is its closed-bottom bowl. When I removed the chopping blade, the onions stayed contained inside. With the Cuisinart, small pieces could fall through the opening around the central drive shaft while I was transferring the food.

Purée Test

Next, I wanted to see how well each machine could purée food, so I made two batches of hummus using the same ingredients and quantities.

Starting with the Ninja PREPi, I added chickpeas, lemon juice, tahini, water, salt, and olive oil, then ran it on high for 30 seconds.

The ingredients were well mixed, but the hummus was still pretty thick and grainy. So I gave it another 30 seconds, and it got a lot smoother, but it was still a little grainy.

With the Cuisinart, I used the same ingredients and ran it for the same amount of time.

But after the first 30 seconds, the hummus was already noticeably smoother than the Ninja’s. And after a full minute, it was even creamier, with a more consistent texture throughout.

Processing Time	Ninja PREPi	Cuisinart
30 seconds	Thick and grainy	Noticeably smoother
60 seconds	Smoother, slightly grainy	Creamier and more uniform

Both batches tasted good, but the Cuisinart definitely made smoother hummus in the same amount of time.

The difference wasn’t enormous, and I wouldn’t avoid the Ninja just because of this test. But if you regularly make hummus or other thick purées, the Cuisinart has an advantage.

Slicing Test

One of the most useful features of the Ninja PREPi is its reversible slicing and shredding disc.

One side slices and the other shreds, so you just flip it over depending on what you’re making.

To test the slicing side, I fed a large English cucumber through the Ninja, and it sliced the entire thing in about four seconds.

The slices were almost perfectly uniform, and there was very little waste.

With the Cuisinart, I initially tried using the smaller feed chute, but the cucumber got stuck halfway through because it was too wide.

So I tried again after trimming another cucumber down to fit through the smaller opening. This time, the slices came out just as even as the Ninja’s.

The Cuisinart also has a larger feed chute that I didn’t use for this test, so the initial problem was related to the opening I selected rather than its overall slicing ability.

It took me about a minute to slice the cucumber with a knife. The slices were pretty even, but not quite as consistent as the Ninja’s.

Next, I wanted to see how the machines handled something softer, so I sliced Roma tomatoes.

With the Ninja, I put a whole tomato into the large feed chute. It sliced it quickly, but several pieces were uneven and a little mangled, and there was quite a bit of juice in the bowl.

For the Cuisinart, I cut the tomato in half so it fit into the smaller feed chute. The slices came out cleaner and more consistent. Keeping the tomato more secure appeared to help.

With a knife, I sliced the tomato in about 12 seconds. The pieces were clean and even, and there was noticeably less juice and mess.

One thing I learned from using the slicing function several times is that you get the most consistent slices when the food fits snugly in the feed chute, without being so tight that it gets stuck.

The Ninja has three feed chute sizes compared with two on the Cuisinart, which gives you a little more flexibility to find the right fit.

Here are the approximate opening dimensions:

Feed Chute	Ninja PREPi	Cuisinart
Small	1.5-inch diameter	1.75-inch diameter
Medium	3 × 2 inches	Not available
Large	5.5 × 2.5 inches	4.25 × 2.8 inches

I particularly like the Ninja’s medium chute. It’s useful for ingredients that are too large for a small circular opening but might move around too much in the larger one.

Shredding Test

To test the shredding function, I flipped the Ninja’s reversible disc over and fed two peeled carrots through the small feed chute.

Each one was shredded in about five seconds. The pieces were thin and even.

The Cuisinart was just as fast, and the results were good, but the shreds were a little thicker. I also noticed a few small chunks of carrot left on top of the disc.

Using a box grater, it took me about a minute and 15 seconds to shred the same amount of carrots, and it required a lot more effort.

I also tested both machines with blocks of cheddar cheese.

The Ninja shredded the entire block in seconds, and the pieces came out nice and even.

The Cuisinart also did a great job, but just like with the carrots, the shreds were a little thicker, and a small chunk of cheese was left sitting on top of the disc.

With the box grater, it took me just under a minute to shred the block by hand. It was definitely more work, and I had to be careful toward the end not to shred my hand.

The Ninja’s slightly finer shreds aren’t necessarily better for every recipe, but I liked that it processed almost all the food without leaving noticeable chunks behind.

Dicing Test

One of the Ninja PREPi’s biggest advantages is that it can dice food into uniform cubes. The Cuisinart doesn’t come with an attachment that can do this.

Just keep in mind that the PREPi is sold in different configurations. The PN351 6-in-1 version I tested includes the dicing kit, but you should check the included accessories before buying another version.

The dicing kit has five parts, including a rotating blade, cutting grid, dedicated spindle, and cleaning tool.

It took me a few minutes to figure out how everything fit together, but once I did, it was pretty easy to use.

I fed two potatoes through the Ninja, and in just a few seconds, they were diced into small, uniform cubes.

Most of the pieces looked great, although there were a few smaller scraps mixed in.

For comparison, I diced two potatoes by hand with a chef’s knife, and that took about 1 minute and 40 seconds.

The Ninja was much faster at the actual cutting. However, that comparison doesn’t include assembling the dicing attachment, trimming the potatoes to fit, or cleanup.

I also tried dicing a bell pepper, carrot, and tomato. The bell pepper and carrot both came out great, with nice, evenly sized pieces.

The tomato got stuck at first, but after I adjusted it, it went through easily. The pieces came out great for something like pico de gallo.

One thing I noticed is that food gets stuck in the cutting grid. Ninja includes a little plastic tool to push it out.

If you’re switching between different ingredients and don’t want them mixed together, you’ll need to clear the grid each time. Otherwise, the next ingredient will push out whatever was left behind.

The dicing attachment is a big reason to consider the PREPi over a traditional food processor. It works well and produces a type of cut that a standard chopping blade can’t replicate.

But it’s also the most complicated attachment in the package. For two potatoes, I’d probably just use a knife. For a large batch of diced vegetables, the Ninja becomes much more appealing.

Crinkle Cut Test

The Ninja also comes with a crinkle-cutting disc that makes wavy slices you can’t make with a regular chef’s knife.

The Cuisinart doesn’t include an attachment for this either.

It works just like the regular slicing disc, except the blade is wavy instead of straight.

I fed potatoes through the Ninja, and in just a few seconds, they came out with nice, even ridges.

It’s great for making homemade potato chips or crinkle-cut pickles.

I fried the potatoes afterward, and they came out delicious. I’m not sure how often I’d use this attachment, but it worked really well, and it’s a fun extra feature to have.

Design and Ease of Use

Besides performance, there are some important differences in how the Ninja PREPi and Cuisinart are designed.

Bowl size and storage: The Ninja comes with a 5-cup bowl and a 7-cup bowl. Both have storage lids, so you can prep food and put it straight in the fridge.

The Cuisinart has a much larger 14-cup bowl, making it a better option when you’re preparing large batches of food.

Controls: The Ninja PREPi has five settings: Chop, Disc, Pulse, Low, and High. Chop automatically runs three timed pulses, while Disc runs for 20 seconds before shutting off. Low and High run for 15 and 30 seconds, respectively, and Pulse lets you control how long the blade spins. The Cuisinart is much simpler, with just two controls: On and Off/Pulse. I prefer the Cuisinart because I can control exactly how long it runs without selecting different programs for different tasks.

Visibility: The Ninja has a large motor pod that sits on top of the bowl. This makes it difficult to see the food while it’s processing unless you bend down and look through the side.

The Cuisinart’s bowl sits above the motor base, and it’s much easier to see what’s happening inside.

Attachments: The Ninja’s reversible slicing and shredding disc is easy to install. But with all the extra functions, you have more attachments to assemble, clean, and store.

The dicing kit is the best example. It works well, but has several parts that need to be assembled correctly and cleaned afterward.

Cleaning: In my onion test, hand washing either food processor took about two minutes.

The Ninja also has dishwasher-compatible parts, although you need to follow its specific care instructions. The blades and discs are extremely sharp, so I recommend using a handled brush when washing them by hand.

The PREPi offers more flexibility than the Cuisinart, but that versatility comes with additional complexity.

Bottom Line: Is the Ninja PREPi Worth Buying?

After all that testing, I think the Ninja PREPi is an excellent compact food processor. It chopped onions and carrots more evenly than the Cuisinart, and its slicing and shredding attachments performed really well.

But what sets the PREPi apart is that it can dice vegetables into uniform cubes and make crinkle-cut slices, two things the Cuisinart can’t do with its included attachments. It’s also smaller and lighter, and both processing bowls come with storage lids, so you can prep food and put it straight in the fridge without transferring it to another container.

I’d recommend the Ninja PREPi if you regularly prepare vegetables, meal prep, or specifically want the ability to dice and crinkle-cut food. If you need more capacity, prefer simpler controls, or regularly make purées, I’d go with the Cuisinart Custom 14-Cup.

One thing to keep in mind is that a food processor doesn’t always save time. Both machines process food incredibly fast, but once you factor in prep, setup, and cleanup, they’re not always the most convenient option, especially for smaller quantities.

If you only occasionally chop vegetables or shred cheese, a good chef’s knife and box grater might be all you need.

You can check the latest prices for the Ninja PREPi and Cuisinart 14-Cup food processor on Amazon.