I ha a life proof case and hated it. They aren't too thick at all, just the plastic screen killed the responsiveness of the touch screen so much. On top of at, they are only good for up to seven feet of water, and I couldn't even get the phone to respond while I was trying to take underwater photos. The only plus was that it truly did keep the water out, which was nice.
I also had the e13ctron bumpers for the 4s and had only three concerns with them. First, they made the phone feel so much taller, which could actually be an issue with the elongated iphone5. Second, they offer no protection for the screen, and third, any wear and tear on them shows, as any drops shred the paint right off. The best thing about them is that I never saw anyone one else with one, so it was kinda neat having people admire them.