I have lived mostly in the country in the western states. In my experience, while T-Mobile can be cost-effective, T-Mobile sometimes has connectivity problems (especially with data) in the sparsely populated areas; but T-Mobile has a good reputation in cities. Also, take care with T-Mobile because it uses less-standard data frequencies. Therefore, I prefer the pay-as-you-go carriers like StraightTalk, Tracphone, or Net10 (which are all part of the same corporation). These use the AT&T GMS system (and also CDMA is available), providing reliable voice, SMS, and data, but generally do not allow roaming. On my Galaxy Note, I ended up with the StraightTalk $50/month plan (unlimited voice and SMS, and actually 2GB data), which has been reliable, if an overkill for me.