It was a rainy Sunday in my tiny kitchen. I was so hungry and very tired of washing dirty pans. My kids begged for hot fries, and I just craved a juicy roast chicken. That was the day I needed a new cooking tool. I tested the Ninja SL400 Vs SL 401 to see which one wins.
Ninja SL400 Review

The Ninja SL400 is a sleek cooking beast. It promises to cook big meals super fast. I pulled it out of the box right on my counter. It looks great and feels very tough.
Pros and Cons
Here is what I loved and hated about this model. It has some clear high and low points.
| Pros | Cons |
| Cooks food very fast | A bit heavy to lift |
| Saves your counter space | The fan sounds loud |
| Fits really big meals | Top racks are a reach |
Living With The SL400
I have used this daily for two months now. The air smells like fresh baked cookies or hot wings. It makes my cooking chores so much easier. I can toss in cold chicken breasts. They always come out juicy and piping hot.

But it is not totally perfect all the time. Sometimes the top rack cooks much faster than the bottom rack. I have to swap the food trays halfway through. Even so, the loud, crispy crunch on my fries makes me smile every single day.
Recommendation
The Ninja SL400 is perfect for busy parents with small kitchens. It is not good for folks who just want to cook a single tiny snack.
Ninja SL 401 Review
Next up is the mighty Ninja SL 401. This model packs a huge punch for home cooks. It stacks the food high to save even more space. I tried it out on a loud Friday night with friends over. We needed hot snacks fast, and this thing delivered.

Pros and Cons
Here is my quick take on its best and worst traits. The good traits heavily outweigh the bad ones.
| Pros | Cons |
| Huge food capacity | Tall design hits some low cabinets |
| Cooks four things at once | Menu buttons feel a bit stiff |
| Very easy to wipe clean | Big trays take space in dishwasher |
Testing The SL 401 Limits
After a couple of months, this fryer feels like an old friend. I use it for my big Sunday meal prep all the time. The rich smell of roasted garlic fills the whole room. It is a pure joy to cook huge batches of food at once.

Cleaning up is a total breeze too. The non-stick surface works like magic against stuck cheese. A quick wipe, and the sticky grease is totally gone. It makes me laugh at how much time I used to spend washing heavy metal pots.
Recommendation
This air fryer is a dream for big families or party hosts. It is not good for people with very low upper kitchen cabinets.
Detail Comparison for Ninja SL400 Vs SL 401
Now for the real test. Let’s see how these two machines stack up against each other. Here is the detail comparison for Ninja SL400 Vs SL 401. I judged them on five main things.
Capacity & Size: Ninja SL400 Vs SL 401
Both machines fit a lot of food inside. The SL 401 feels just a bit bigger for large cuts of meat. The SL400 fits much better in tight, cramped spots.
| Feature | Ninja SL400 | Ninja SL 401 |
| Basket Size | 9.5 Quarts | 10 Quarts |
| Counter Space | Small Footprint | Small Footprint |
Rating: Ninja SL400 (8/10), Ninja SL 401 (9/10)

Cooking Performance: Ninja SL400 Vs SL 401
Both fryers cook fast and make your food very crispy. The hot air flows well in both models. I noticed the SL 401 keeps the heat a little more even.
| Feature | Ninja SL400 | Ninja SL 401 |
| Crispy Crunch | High | Very High |
| Heat Flow | Good | Great |
Rating: Ninja SL400 (8/10), Ninja SL 401 (9/10)
Ease of Use: Ninja SL400 Vs SL 401
You can learn to use both models in just five minutes. The digital menus are very clear and bright. The SL400 buttons just feel slightly nicer to press.
| Feature | Ninja SL400 | Ninja SL 401 |
| Menu Screen | Bright | Bright |
| Button Controls | Smooth | A bit stiff |
Rating: Ninja SL400 (9/10), Ninja SL 401 (8/10)
Cleaning & Maintenance: Ninja SL400 Vs SL 401
Nobody likes washing dirty dishes after a meal. Both fryers have parts you can put right in the dishwasher. The SL 401 trays wipe clean just a bit faster by hand.
| Feature | Ninja SL400 | Ninja SL 401 |
| Dishwasher Safe | Yes | Yes |
| Hand Wash Ease | Good | Great |
Rating: Ninja SL400 (8/10), Ninja SL 401 (9/10)

Build Quality & Design: Ninja SL400 Vs SL 401
These are tough machines built to last. They look like cool robots sitting on my counter. The SL 401 is taller, which looks nice but can bump low shelves.
| Feature | Ninja SL400 | Ninja SL 401 |
| Material Build | Tough Plastic | Tough Plastic |
| Style and Look | Sleek | Tall and Modern |
Rating: Ninja SL400 (9/10), Ninja SL 401 (8/10)
Conclusion
Both models are fantastic choices for your daily cooking chores. The SL400 wins on pure simple design and smooth controls. The SL 401 takes the crown for huge batch cooking. You will be very happy with either one you pick!