Loving my Speck case!
One of the other posters commented on how the case makes the (camera) buttons more easy to press.
That is one of the reasons why I like the Speck case - it makes manipulating the power/sleep button much, much easier. And, unfortunately, since there exists no reminder apps for missed calls/SMS/etc., one must manipulate the phone quite a bit if you don't keep it nearby (AND you're an I.T. guy often on call!).
To combat the problem of the volume controls being pushed too easily, I just shaved, with a razor, the hard rubber of the button to a protrusion of my liking.
The face of the case seems to have been intentionally designed to keep the glass off surfaces when the phone is placed face-down. If the phone were worn in tight pants/pockets, I could see where the case might be pushed back by the "lips" of the case, thus exposing an edge or two of the screen protector, OR snagging an edge as the side of the case returns to its designed fit. I've worn the phone in my pockets quite a lot in the past 14 months and have not had an issue with the screen protector.
Still, LOVE the case. I've only seriously dropped the phone once (in a parking lot), but the case protected it nicely.