Is there even a single other country where the iPhone has the problems it does on AT&T? I've been using my 3G on Rogers here in Canada since it was released. I've never seen a dropped call and Rogers' network is consistently faster than the phone.
I can't remember having ever dropped a call on my iPhone 3G and the network is absolutely rock solid, and very very fast (using the Xtreme Labs speed test app, for example).
The logic of this article in compelling at first but doesn't stand up to evidence that the iPhone is quite good outside of AT&T.
I've also used it in Montreal with similar experiences. So either the Canadian 3G networks are especially good, or AT&T's network is crap.