I don't think so, and, in fact, this topic was discussed briefly on This Week In Google (TWIT.TV). The founder of GigaOM said he had the same poor service w/ his iPhone as the rest of his ATT phones.
That said, the whole concept of ATT sucks is 100% depending on where you are. Before the iPhone I had Sprint. I would lose the signal as soon as I was in my garage (door didn't even need to be closed). W/ ATT I get 5 bars all over town and my 3G speed is a hair faster than my home DSL (3.1 mbps vs 2.8).
I was in SF last summer and service was pathetic. No way would I own and iPhone there and I don't know why people there put up with it.