I use T-Mobile wireless phone service. It is unreliable. People tell me that they get some kind of "cannot connect" error often when they call me, even though my phone indicates that it is getting good signal strength from the base station. Therefore, I must believe that T-Mobile has oversold and underbuilt their network. Also, their GPRS-based web access is horrible. It is extremely slow and unreliable. However, I think that it is good that they are trying. The mistakes that they are making now will help push wireless technology forward.