Look for a large capacity (5 qt +), multiple cooking functions (air fry, roast, bake, dehydrate), and a high maximum temperature of at least 450°F for crisp results. Adjustable fan speeds and precise temperature controls help achieve even cooking, while a non‑stick or ceramic coating simplifies cleanup. Also consider a digital interface with preset programs for convenience.

Both models reach 450°F, but the Ninja uses Max Crisp technology with a single powerful fan, while the Cosori employs a 5‑fan TurboBlaze system for more uniform airflow. The Ninja offers a slightly larger basket (6.5 qt vs. 6 qt) and includes a dedicated dehydrate function, whereas the Cosori highlights its premium ceramic coating for durability. In practice, the Ninja may handle larger batches better, while the Cosori provides finer temperature granularity.

Dual‑basket models like the Ninja DZ201 let you cook two different foods simultaneously, saving time and avoiding the need to re‑heat or swap trays. They typically have a higher price tag and a larger footprint, but the ability to finish meals together can be valuable for busy families. If you often prepare separate sides or want to keep flavors distinct, the investment pays off.

Glass containers provide a clear view of the cooking process, allowing you to monitor doneness without opening the lid. They are also oven‑ and microwave‑safe, so you can transfer the container directly for finishing or reheating. However, glass units may be heavier and lack the ruggedness of metal baskets, so consider your storage space and handling preferences.

Ceramic and PFAS‑free non‑stick coatings reduce the need for oil and make cleaning easier, while also resisting scratches and high temperatures. Bare glass containers avoid any chemical coating altogether, eliminating concerns about coating wear over time. Choose a coating based on your cleaning habits and whether you prioritize a completely coating‑free cooking surface.

Smaller units can achieve comparable crispness because they heat up faster and use concentrated airflow, but they handle less food per batch, which may require multiple cycles for large meals. Larger models provide more uniform heat distribution across bigger volumes, reducing the need for batch cooking. If you value speed over volume, a 4‑qt portable fryer is a good choice; for family gatherings, a larger capacity is more efficient.

Presets for popular dishes, a rotisserie attachment, and a Smart Finish or Match Cook function can simplify cooking and reduce trial‑and‑error. A dishwasher‑safe basket, removable crumb tray, and a clear digital display add convenience and ease of maintenance. These extras often justify a higher price by saving time and extending the appliance’s versatility.

None of the listed models are explicitly made in Japan; most are produced in China or other Asian factories. Japanese‑made appliances are known for precise engineering and long‑term reliability, but the performance of a specific model depends more on its design features than its country of origin. Focus on the specifications, warranty, and user reviews to ensure you get a high‑quality air fryer regardless of where it’s built.