GSM Advice in California and Arizona

[AndrewP]

I'm looking for some advice on GSM coverage in the California to Arizona area.

In September, my wife and I are going on a bit of a road-trip for several weeks in the west of the USA. Starting out from San Francisco, we'll be doing a loop that pretty much takes in Las Vegas, Phoenix and Los Angeles before returning to SF.

Obviously I'll be taking my unlocked GSM Treo and to avoid horrendus charges on my UK-based plan, I'll purchase a pre-paid GSM SIM.

I've looked at the coverage maps, etc. but nothing beats personal experience. Would anyone like to recommend a provider for this area or is it now much of a muchness?

I was looking at Cingular and T-Mobile, in that order. Sprint's web site was rubbish and I couldn't figure out if they even offer a prepaid / pay as you go.

Is there anything else important I should know about using a prepay in the USA? What's the story with "roaming"? In Europe, you roam if you go to a different country - sounds like you roam in the USA if you leave you local area.

Thanks,

Andrew

[zackepceo]

The US networks have to cover such a big area, they can't be complete, so there's roaming between the two national GSM carriers and lots of the smaller ones. I've heard that T-Mobile has a much better California network, but you might roam in Arizona. Cingular's California network is being redone because they purchased AT&T Wireless and has issues with selecting the correct network for the area. There is no extra cost for domestic roaming.
You have to pay for calls you make and for incoming calls, which is different than how European services work. Incoming SMS and MMS messages are free on T-Mobile.

[rhart00]

Very happy customer of Tmobile in Southern California for over 3 years. No major service problems. If you know exactly where you are going on your trip, TMobile has street level service coverage maps on their website that can be pretty handy.

[dragonsgames]

Sprint doesn't even have SIM cards ;)