I'm pretty close to dumping AT&T and making use of my unlocked phone. I'm curious about others experiences with T-Mobile recently, especially if someone else has an iPhone on their network. I may aim for the $30 a month unlimited data and text plan, with 100 minutes. Just debating if that will be enough talk time each month. The other possibility on the talk side is to port my number to a VoIP service, but I worry about reliability of VoIP over wireless data networks and integration with the iPhone.

Coverage areas that interest me are around Austin and other parts of Texas, front range of Colorado, Seattle, Portland, and Orange County, CA. From what I can tell, most of these areas have had the frequency swap already occur to allow iPhones 3G (what T-Mobile brands 4G) access.

I sometimes use VoIP with Verizon 3g and 4g. I only recall being dropped once. However the latency can be very annoying. 4g is better but it still bugs me.

I have had poor experiences with T-mobile coverage in the Seattle area. They seem to be really spotty up here. For that matter, same with Sprint, they are also quite spotty up here.

Interestingly, I have been super-happy with AT&T coverage in the Seattle area. It's quite good up here, with strong signal in any place I want it. I have seen better signal coverage from AT&T than I have seen from Verizon in the Seattle area.

In order of best to worst coverage for Seattle, my experience has been:
- AT&T
- Verizon
- Sprint
- T-Mobile

... With only AT&T and Verizon being above the bar of what I would consider usable.

If you do end up going with TMobile I'll be interested in your experience. I'll be doing something similar, although I need the unlimited minutes.

I'm also concerned about their data speeds.

I think what I'll do is pick up a SIM and try it out. After a month, then I can decide if I want to port the number. Best part, I can toss the SIM in the iPad for data and do side by side comparisons with AT&T.

Not sure why I didn't just think of this earlier. This is the problem with the contract subsidy market, it changes your thinking to assume locks are present everywhere in the mobile market.

Don't just pick one up in the store if you intend to use the $30 Walmart plan. Word is that T-Mobile is segregating store-bought SIMs. Only those bought on tmobile.com or ones that come with a Walmart phone are eligible for that plan.

T-Mobile store employees are also unable to provision a phone or SIM with that plan. It has to be done on the website or in a Walmart store.

In NYC, T-Mobile is great. Where I live is on EDGE service basically from here to Albany. Along the New York State Thruway, if you glance at your phone, you're either on EDGE or in a dead zone. It's evident that T-Mobile has a long way to go.

$30 is a great deal for that plan, buy only if you spend the vast majority of your time in the right places.

It's like the T-Mobile/Orange setup here in the UK. They have merged into EE which is the only 4G provider in the UK right now - the problem is 4G is only set up in certain cities, so I can use 4G in Edinburgh and Glasgow, and for major bits of the route home, but the gaps have almost no connectivity, and I'm back to 3G by 400 yards from my house.

Which is a pity, as 4G is 5 times faster than my home broadband :-/