Might have been me -- I recently got the PDAir vertical case (the one with a belt clip). So far, it's been perfect; even when I'm not wearing it on my belt, I keep the phone in it for protection.

But yeah, it grips the phone fairly tightly, and the inner surface is a roughened, slightly rubbery material (maybe a vinyl surface?) that can rub against the phone as you slide it in or out of the case. I wouldn't want to use it without a screen protector.

Right now, I'm using a "Lexerd TrueVue" screen protector, which has worked well for almost two months. But I don't really know how well it stacks up against other screen protectors.