I've had one on my iphone since day 1. It changes the finish from super glossy to matte, and that is the only noticeable difference. It won't even pick up fingerprints nevermind a scratch. Case-wise I got an expensive case (supposed to be very good) and it broke the first time I dropped it > and it also scratched the backside of the phone pretty badly.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth