What's the inside like?
Does it have a soft material on the inside where the iPad sits? That's pretty critical - some have hard plastic, and there's a big issue with that. Tiny bits of dust and grit get into it, and get trapped between the iPad and the case. Over time as it all moves about slightly, the bits of grit get ground into the metal and you end up with marks all over it. In that case you might as well not bother protecting the back.