I don't have this exact one but I love my air fryer.
You don't have to heat up the oven, the grates vs a baking sheet bake the foods without sitting in the grease, I'm not sure about saving time but I like that it's countertop, easy to use, heats up fast and overall unless you're cooking for a large family, a small unit.
There's actually no instructions that I know about, I set the temp that something normally bakes at, set the timer and let it go.
I bake french fries, fish, chicken and rolls. I clean the grate, wipe and bottom and we're good to go to the next time I use it.
Sorry you don't like yours.