I have the 9 in 1 which does pressure cook, air fry, slow cook, steam, bake, roast, sear sauté, grill, yoghurt and dehydrate.
I use the pressure cooker to cook a full chicken it takes 30 mins, then I air fry it for 45 mins.
I do the same with roast potatoes which is 3 minutes pressure cook, then about 45 mins air fry.
I have also cooked the veg to go with this for the same as above time wise. When things are air frying you have to open the lid and give them a bit of a stir round. It's very easy.
The only ball ache for me is that you have to add the pressure cooking lid, then remove it and use the attached lid for air frying - this is really easy you can't mess it up.
You can get the next model up which I think is the 15 in 1 where you don't have to change the lid.l when pressure cooking.
I've also made yoghurt and dehydrated pineapple and mango with it.
Not yet tried the steam, bake or roast options but I will do next time we do a joint of meat.
I normally see what I want to cook then google how to do it. There are loads of videos on you tube.
What I will say though is that it's quite big and heavy so you need space on your worktop to put it and leave it. It's too heavy to get in and out. It will need to be open above the ninja aswell as when you pressure cook, you turn a little valve on the lid to release the steam and I can imangine if you did this under a cupboard for a period of time it would ruin your cupboard.
I really like mine and I use my oven and hob much less.
It's a lot easier making a roast in it as there is only the ninja pan and grill pot to clean rather than loads of pans. The chicken always comes out lovely. Not dry at all.