Coverage concerns...I think all carriers are imperfect as far as coverage, but after a few expected gliches I imagine Cingular's coverage will be much enhanced after the AT&T merger.
Even Verizon coverage is spotty...my wife and daughter's previous Verizon phones didn't even work well standing outside in the parking lot at the High School, and this is a HS with over 1500 students and is less than 1/2 mile from a major interstate highway and only 30-40 miles from Houston. They use to get a kick out of that "Can you hear me know?" Verizon commercial.
We are all on a Cingular family plan now, and my Nokia GAIT phone (tri-mode GSM, TDMA, Analog) has excellent coverage. My only regrets are that I didn't sign up for more minutes, and IDCC hasn't been paid the royalty they deserve.