Ninja PREPi 6-in-1 Prep System PN351 review

The Ninja PREPi PN351 is the dicing-equipped Copper + Teal version of Ninja’s compact prep-and-store processor. Its box distinguishes it from the standard PN301: the PN351 item list includes a dicing kit alongside the 5-cup and 7-cup bowls with storage lids, crinkle disc, reversible slice/shred disc and chop/purée blade. If diced vegetables are central to your routine, that included accessory is the practical reason to choose this model. If not, the PN301 has the same basic bowl-and-disc arrangement without the dicing kit. Neither version should be mistaken for an eight- or fourteen-cup workhorse simply because Ninja markets it as a complete prep system.

What the package does—and what is not established

The official page names six functions: dicing, crinkle cutting, chopping, puréeing, slicing and shredding. The dicer is listed as an included kit; the other main cutting tools are a crinkle-cut disc, a reversible slice-and-shred disc and a chop/purée blade. The two bowls have different stated capacities, 5 cups and 7 cups, with a storage lid and spindle for each. Ninja describes preparation, serving and refrigeration in those bowls. These are useful convenience features for keeping a modest amount of prepared ingredients in the same container. The largest bowl rating is seven cups; the product page does not supply task-by-task maximum loads or a separately measured usable batch yield.

Published body dimensions are 9.3 by 9.3 by 10 inches and the listed weight is 12.69 pounds. It is corded, rated at 120 volts and 500 watts, has a 31.5-inch cord, and carries a one-year limited warranty. The compact footprint may suit a smaller counter, but use those published dimensions only as the machine’s body size: leave room for the feed chute, pusher, lid and your hand position. The official page calls its chute a three-part design, not an extra-large chute, and it does not tell the buyer what maximum ingredient dimension will fit. Measure both storage and working space rather than relying on “compact” alone.

Decide whether the dicing tool is worth the package

The PREPi family illustrates why exact-package comparison matters. PN301, PN301B1 and PN351 share much of the same architecture, but the base PN301 is listed without dicing. The PN301B1 bundle pairs the blue PN301 system with a separate dicing kit; the PN351 itemizes its own dicing kit and uses Copper + Teal trim. Ninja’s PREPi dicing accessory is also offered separately, but if the ability to dice is essential immediately, buying a package with the kit explicitly listed is the clearer route. Do not infer that an image showing an attachment or a family heading covers every configuration.

The official pages describe fast and even dicing, and the product listing repeats a claim about dicing several potatoes quickly. Those are manufacturer claims, not a test performed for this review. No independent timing, cut-consistency, waste or cleanup result is available here. The PREPi page also does not give a millimeter measurement for the grid. Treat an essential cube-size need as unknown until it appears in a manual or package document. The seven-cup bowl remains the system’s largest rated capacity.

How the PREPi fits everyday preparation

The paired bowls address a familiar nuisance: switching between a processing container and a separate dish for leftovers. A 5-cup bowl can hold a smaller prep job while the 7-cup bowl stores another, and both listed lids support the manufacturer’s prep/store use. The reversible disc reduces the need to keep two separate slice and shred discs for those basic operations, while the crinkle disc expands the cut options. This is a reasonable match for a cook who prepares small amounts of produce, toppings or ingredients across several meals. It is less persuasive for a household whose weekly batch routinely exceeds the largest bowl or that expects one machine to knead a manual-specified bread dough, handle large nut loads, or provide adjustable slice thickness. The package does not list a dough blade, a French-fry disc or an adjustable slicer.

For a larger bowl, compare against an exact larger-capacity machine rather than stretching the PREPi rating. A nine-cup processor offers more stated bowl space, while larger models may also include task-oriented discs or a dough blade; those differences vary by package. A dicing function alone does not make the PN351 equivalent to every full-size processor, and the broader appliance names do not guarantee a particular cut or batch size.

Manual and cleanup caveat

Ninja’s category comparison lists the PREPi as dishwasher-safe. However, the support link from the PN351 product page routes to a support endpoint that returned a 403 response during this review, and no exact PREPi instruction booklet could be inspected. The exact top-rack recommendation, care for the dicing grid, safe blade handling, processing maxima, motor-on interval and overload/cooldown instructions are therefore unknown. Do not treat the category-level phrase as a substitute for the unit’s care chart. Before first use, consult the printed directions that ship with your exact PN351 and keep fingers away from the sharp disc and dicing grid while assembling or washing it.

Bottom line: PN351 is the PREPi choice when you want a compact two-bowl prep-and-store system and want a dicing kit included in the Copper + Teal package. It adds real tool versatility over the base PN301, but it does not add bowl capacity or verified task limits. Choose PN301 to save the dicing package when it is not part of your routine; choose PN301B1 for the same included-dicer idea in the blue PN301 bundle. If your essential need depends on a documented millimeter grid, a batch above seven cups, a precise manual duty cycle or a specific cleaning-rack rule, resolve that requirement from the exact operating instructions before buying.

Sources: Ninja U.S. PN351 page; Ninja U.S. PN301 page; SharkNinja launch announcement. Marketing performance statements remain attributed and untested.