They save a lot of smell, heat up quickly and use loads less energy
Yes, a lot quicker and a lot cheaper.
Oven - wait 20 mins to get to temp, put in food, wait x minutes to cook.
AF - Put food straight in, wait (x-5 mins) to cook, resulting food is often much better. Chicken is more moist, no hot spots i.e. burnt on one bit an uncooked in another. Easy to clean, and you can use foil or Air Frier paper liners so you don't have to clean it at all.
Only problem is, and something to consider: Ours has one tray and is small. When it's time for a new one we might go with a dual-tray. So you can perhaps do burgers and chips separately without the burger fat leaching onto the chips.
The only thing we use the AF for now is pizzas, which won't fit in the AF. There are air friers that are large enough for pizzas but that's getting into small oven territory where you'd be hard pushed to recoup any savings on the outlay.
As an aside - I saw a marketing psychologist talking about air friers, and he said they really missed a trick with the naming and marketing. Air friers tend to suggest frying (fat) and are often catalogued alongside deep fat friers. Had they been named "Air Grills", or similar, they would assume the position of a healthier product in line with George Foreman grills and steamers