I've had T-Mob for three years now, and several benefits are: 1 year contracts, free phone upgrades after a year, GSM technology, unlocked phones on request after a year, overseas roaming, very competitive plans, including family plans, good major market coverage, all-local-all-the-time calls (no roaming, no long distance,) $.05/minute calls to Mexico and Canada - that's cheap, folks! And, voice transmission quality with my Moto V190/V360 series phones has been crystal clear with 1 bar or more signal strength. On the customer service side... other than the stupid initial computer generated person you have to get past, once you're dealing with a real person I find the service to be 1st class, and I've had a few discussions at length with extremely knowledgeable and informally pleasant cust. serv. agents.
Of course, in rural areas, the service is definately more spotty, and at times non-available... but I just wait a few minutes and I'm usually back in range. Somebody said the voice mail at T-Mob wasn't customizable, whatever that means..?? but certainly you can change and record your own message just like with any other service, and I see no difference there.
On the towers, well, T-Mob builds their own towers, and has some kind of mutual agreement with Cingular (formerly AT&T GSM) to use their towers for roaming, and vice versa. Fairly invisible to end users. In fact, I submitted our property on the Oregon coast to t-mobilelandlords.com for consideration as a new tower location. Bottom line: other than the lesser coverage areas compared to Verizon, there's not a thing wrong with my servicel, or the phones they provide. And with my two older phones, when I'm going out to do something physically risky, I just slip my SIM card out of my new phone, and put it in my older Nokia in case it falls in the river. All my phone numbers are duplicated on my new phone's internal memory as well as the SIM, so it's nice having a spare/backup couple of phones in the drawer. Try that with CDMA.
By the way, if you see more 11 yr olds w/ T-Mob phones, it's probably because their parents saw it as a cheaper family plan alternative to the competition. I doubt the kids made the decisions. Can you hear me now?
Now, come on Apple. I'm waiting!