Surely, someone has asked people in other countries what their experiences are with their iPhones on their carriers. Given that the rest of the world is on GSM (Korea excluded), we should pretty well know whose fault it is.
Here's my anecdote. I'm an iPhone user in Canada o the Rogers network. My signal is very strong everywhere. I rarely see any less than a perfect signal, except when far away from metropolitan areas. Usually five bars, indoors and out. I may have had a dropped call over the last year, but I couldn't tell you when.
Last week I visited mountain view for Campfire One. In the three days I was there, I had two calls dropped on me. One of them was dropped while walkig around outside at the Googleplex. My signal often wavere between zero or two bars and five bars for no explicable reason. I would occasionally lose signal entirely inside buildings (my hotel room for one).
In my experience, a perfectly working iPhone in Canada becomes unreliable in California. Take from that what you will.
I've used my iPhone in San Francisco, Houston, Buenos Aires, Montevideo and Santiago. AT&T in the US, other carriers in South America (my phone is unlocked and I have different sim cards). I can say that AT&T worked much better in Houston than in SF. Claro in some parts of South America is better than AT&T in SF too (it varies from city to city).
I can't speak for mmastrac, but in general Rogers devices roam onto AT&T as their first choice. I've noticed similar lameness in AT&T's network while traveling...
Last week I visited mountain view for Campfire One. In the three days I was there, I had two calls dropped on me. One of them was dropped while walkig around outside at the Googleplex. My signal often wavere between zero or two bars and five bars for no explicable reason. I would occasionally lose signal entirely inside buildings (my hotel room for one).
In my experience, a perfectly working iPhone in Canada becomes unreliable in California. Take from that what you will.