As someone else said iPhone 3G i great - shame about the battery. I abuse my one. RSS / games and Music over bluetooth headphones on the morning commute and again throughout the day. WIFI / 3G surfing during the day and a bit of GPS navigation from time to time in the evenings. My battery used to die every single day before I got home. This saved me! The battery is full when I get home :D - love it!
Drawbacks...my previous case had a card holder section and was a side-opener - I preferred that. Otherwise solid design and decent. Good price.