After refusing to use a case on my iPhone 4 when I first received it, I ended up having to replace my camera lens due to excessive scratches caused from pulling the phone in and out of my pocket. I next moved to the official iPhone bumper, but it fell apart after a few months. Finally, I moved on to the Reveal. It has been great. I wished I used it from day one. Its profile is slim, the button are easily manipulated and the case allows you to use either a slim iPhone headset or standard sized connector.
A word of warning, this case will "fit" an iPhone 4S, but the side mute and volume buttons will not line up. The mute switch is a few millimeters off from its placement on the iPhone 4. You can still flip the switch on the 4S and the volume buttons are still responsive, but if you want it properly lined up, make sure you get a 4S specific case.