I think Fred might be disappointed when he switches back to t-mobile. I was a t-mobile customer for years and I agree they have awesome customer service. The big problem for me was the terrible cell reception in many buildings in NYC.
That said, I hear there are many areas in the US where t-mobile provides decent service. For people considering switching if t-mobile's international data deal isn't that important to you, you may want to check out http://www.solavei.com first. They are a t-mobile reseller (MVNO) and you may be able to save some money compared to going through t-mobile directly. Their prices are similar to straight talk (mentioned in some of the other comments) and they also allow you to refer customers to reduce your monthly bill.
Best cell phone service for the price IMO is http://www.pagepluscellular.com/ (a verizon reseller). $55 / month (including taxes and fees) for unlimited calling, unlimited texts, and 2 gigs of data. I have been a customer of theirs for a year and a half. Their customer service is pretty good, but more importantly their signal strength (coming from verizon's towers) is the best out of all the carriers in NYC.
The one big caveat with the MVNO resellers is that they don't offer LTE data and some don't support LTE phones (ie iphone 5, 5c, 5s, etc).
TL;DR - if you're down to use an iPhone 4S or other 3G smartphone you can save some serious money per month going through an MVNO reseller.
As far as I know, the signal strength for voice calls and the data speed are different issues. Many T-mobile towers only support edge (1x) speeds on non-LTE GSM phones. Some towers have been refarmed to support the 3G hspa+ frequencies. Here is an unofficial coverage map:
http://www.airportal.de/
In my apartment in the Upper West Side, I was getting a 3G data on an unlocked AT&T iphone 4S with a t-mobile sim, but only 2 bars of voice service. I'm tempted to try t-mobile's $30 / month 5Gig data + 100 minutes plan to use with my iphone 5s.
If their LTE service has decent coverage I may be able to get away with using facetime audio + google voice + talkatone.
Best cell phone service for the price IMO is http://www.pagepluscellular.com/ (a verizon reseller). $55 / month (including taxes and fees) for unlimited calling, unlimited texts, and 2 gigs of data. I have been a customer of theirs for a year and a half. Their customer service is pretty good, but more importantly their signal strength (coming from verizon's towers) is the best out of all the carriers in NYC.
The one big caveat with the MVNO resellers is that they don't offer LTE data and some don't support LTE phones (ie iphone 5, 5c, 5s, etc).
TL;DR - if you're down to use an iPhone 4S or other 3G smartphone you can save some serious money per month going through an MVNO reseller.