I just became upgrade eligible and took the iPhone 4 plunge. I received it today, but out of the box it's been a terrible experience. My 3GS next to it has 5 bars of 3G. I turn that one off and turn the new one on and I just have No Service. I can't activate it because of this. I've tried toggling Airplane mode, resetting network settings, turning off 3G (just to try Edge only), and lastly I installed the 4.0.2 update (it came with 4.0.1 from AT&T) and it still has No Service. I also popped out the micro SIM tray and put it back in to make sure it was seated properly (even though it wasn't giving me a No Sim message or anything like that.) It was set up as a new phone. I'm out of ideas and I have no time to bring this to a store or anything. Is there anything else to try before I have to send this thing back?