I (EU based) had the possibility to play with a (US) friends IPhone for a couple of hours.... it is a very cool toy, with the usual Apple "Whow" factor. (i.E. few things on this device are revolutionary, but you still crave one) What it is not, is a crackberry killer because it doesn't and will not have push-mail. If you want or need push-mail, forget IPhone V.1
The IPhone's biggest downers in my eyes: you cannot install extra software. You have to do with what's installed on the phone. No possibility to add storage capacity. Built in camera shoots no video. No G3.
The best features: The touch screen and interface, the voicemail feature (Apple style), the screen that turns when you turn the phone, the way it displays your pictures. To me it is a great new IPod Video, with only 8Gig storage and good (but not state of the art) phone capabilities.
Having said all that.... I'll still buy one, once they come out in EU - it's got the "Wow" factor....