I didn't have convection oven neither microwave. I only had old oven. So the Ninjafoodi is very usefull for me for many reasons. It's the best for warming up lunch, cooking  frozen food, wings and veggies like kale. Everything is crispier, faster or/and easier when you use the ninja rather than the baking sheet in the oven. But it's less crispier than cooking deep fried and you can do many things without it. Learn how to use it. For example, use vegetable oil and don't fill the basket completely for the best result.