you guys have the fancy ones. I've just got one that's a basket you drop crap in and it circulates from the heating element /fan above. in general mine's used as a replacement for the slow-to-heat oven/broiler.
awesome for the right things, sucks for some others. Makes awesome pork if you chunk it into 1" pieces and marinate/season it. it gives it a nice crisp like the oven broiler. Fries obviously, breaded chicken, any frozen food it re-heats well, etc. whole chickens are good but I hate cleaning it afterwards. Fried chicken from the supermarket crisps up awesome.
recent discovery was sweet potato wedges. cut them into big wedges, toss in oil and whatever spices, and throw em in like fries. They come out well cooked with a not-mushy outside. I always turned them to mush other ways so I didn't make them often, but i've gone thru 3lbs this week so far since doing them this way.
canned chickpeas are an easy snack out of the fryer. pat dry, sprinkle with whatever seasoning, air-fry for a while and you've got a chips alternate.