Update:
Today, I made chicken wings and they were so good. I was able to fit 8 or 9 Buffalo wings. I shook them about ever 7 minutes and they were just as good as I remember with my 4 qt. Ninja.
I like the taller basket in the 5.5 qt more. It may not fit as much food, but the splatter in the 4 qt builds up, is impossible to clean, and begins to smell after a couple of weeks because it never gets completely clean.
Update: Today, I cooked a Ribeye - well done at 360 degrees for 14 minutes. It was perfect and juicy. The cut wasn't as thick as the first one I tried. It was maybe 0.75 inch thick and the other was 1.5 inches. For a thicker cut, I still recommend going with a lower temperature for longer.
Update: I made buffalo wings, but this time I used Air Roast instead of Air Fry and ommmmmgggg, they were soooooo good. I will definitely be using Air Roast majority of the time going forward. The chicken was more moist and tender. Air Roast is also great for when you want to toss the wings in sauce.
Update: I made a NY Strip steak and it was perfect. I used Air Fry at 360 degrees for 16 minutes and it was perfectly well done. I'll use Air Roast next time to see how that does.