I'm using one. Best screen protector I've ever had just came with my otterbox commuter case. Excellent quality! It's your phone, but I wouldn't take the chance.
bestskinsever (dot) com has the best hands down, I use that with the Otterbox Defender...I'm an AT&T tech so i work outside in all conditions and it's a must have for me
i just got one of those cheap Ultra-Clear screen protectors from Seidio. the ones that use static or whatever it is to stick. real easy to put on. my first try went flawlessly. no bubbles, no dust or anything. i was pleasantly surprised at myself