We have a Ninja Dual, and there's quite a lot of things that you can do in it.
We're a family of 4 and were without a kitchen for about 3 months due to building work, and it was a godsend then. We cooked roasts in in, chicken stuffed with boursin wrapped in bacon, fajitas, chicken wings, chicken thighs, roasted veg, chicken curries, chilli con carne, baked camembert, pork chops, kebabs etc as well as the obvious sausages/bacon/beige food etc.
Now we have normal kitchen facilities back, we do still use it, but obviously less.
I wouldn't cook a whole roast in it, but I would roast a chicken in it to serve with salad and new potatoes to save putting the oven on.
I use it for sides to meals that aren't cooked in the oven e.g. garlic bread with Spag Carbonara or spring rolls with a stir fry or onion bhajis/samosas/pakora with a curry.
It's the best and easiest way to cook sausages and bacon (and as a bonus it never sets the smoke alarm off, which always seems to happen when I grill them).
It's great for hungry teens making themselves cheesy chips or fishfingers/nuggets/burgers etc.
Overall, I'm glad we got ours.