From what I can gather, the biggest problems with the iPhone seem to be as follows, in order of severity:
You can only use AT&T network
The EDGE data network is slow
The keyboard takes some time to learn
Making a phone call can take more "taps" than with other phones
No way to Cut, Copy or Paste
(I'm leaving off the list the fact that so many are having trouble activating their phones. I think this is AT&T's capacity planning problem, and I don't think we'll see this happen again.)
This is remarkable. The iPhone is NOT a simple device. It is a complex feature-laden phone, iPod and web device. And with all this functionality, the most folks can do to complain about it is reference something related to the items above.
This phone flies in the face of all those who think that 1.0 products must be either fully focused on one task to be done well, or those that consider 1.0 products something you should avoid by default until the next release, you know, the one with all the bugs worked out. The iPhone while complex and full of features, does have a simple interaction and experience. It is so compelling and just fun, that to miss out on this version while waiting for the "next rev" seems almost unbearable, once you've played with it. As others continue to market proudly their "alpha" and "beta" stickers, Apple shows us all, that you can deliver a 1.0 experience that really is complete.
What it means to be 1.0 will never be the same.