Buy the Cosori TurboBlaze.

It cooks better than both, and it doesn't die in five months like the Chefman does.

What was compared

Cosori TurboBlaze Air Fryer, 9-in-1, 6 Qt, PFAS-Free Ceramic Coating | 90°–450°F, 5 Level ... — $89.99
Chefman Air Fryer – 6 QT Compact Airfryer for Quick & Easy Meals in Minutes, Features Hi-F... — $69.96
Ninja Flip Toaster Oven & Air Fryer, 8-in-1, Stainless Steel, SP151 | Air fry, bake, broil... — $149.94

1. Beats both in head-to-head taste tests
In the same three-way comparison, reviewers called the Cosori TurboBlaze larger, easier to use, and the best-tasting food of the bunch, beating both the Chefman and Ninja Flip head to head.
2. Chefman dies in months, this doesn't
Chefman owners report units failing at 4 months, 5 months and 11 months, including a control panel that froze up completely. The Cosori shows no matching pattern of early death in the same reviews.
3. Skip the toaster oven bulk you won't use
The Ninja Flip is an 8-in-1 toaster oven hybrid that eats more counter space and, per owner reports, can smoke and develop fan noise over time. Unless you actually want it replacing your toaster too, that's extra bulk and risk you don't need, and most air fryer buyers do not.
4. No forever chemicals in the coating
Cosori's basket uses a PFAS-free ceramic coating, sidestepping the forever-chemical worries that still surround cheap nonstick baskets. Neither the Chefman nor the Ninja listing makes that same claim.
5. Yes, the Chefman is cheaper. Skip it anyway.
The Chefman undercuts it by twenty dollars, but reviewers describe it dying in months, not years, including a stuck control panel and a unit dead at five months. Saving twenty dollars once is a bad trade for a fryer you end up replacing twice.