J.N.
We have been with T-mobile since they were VoiceStream, probably 10 years. We've always had good service with them. My husband is a truck driver aand he's usually on the road so the unlimited mobile-to-mobile with our family plan is definitely necessary. And the coverage has been pretty good. But all service providers have their +s and -s
I'm not sure about the phones. I use a simple RIZR, but my husband has one with all the fancy bells and whistles, and I know they have even more sophisticated ones - he had one that was a PDA, had some sort of internet availablitiy, even had programs like Yancy where he coud download material for reading - he had the entire LDS standard works, hymn book, and lesson manuals on his phone! Plus it was an awesome camera. If you want more details about what kind of phone it was let me know and I'll ask him next time we talk (it'll be today).
Good luck!