I used to be an AT&T Wireless customer, then that became Cingular. Before that I used Verizon.
Verizon used to have horrible customer service in the late 90s, but, they dramatically changed that and now have pretty darn good service for a phone company.
AT&T Wireless was even better than Verizon at the time. Then Cingular bought it and it really went downhill from there. The service itself is mostly good, but, I have no idea what they mean about "fewest dropped calls," because I have dropped calls all the time in the middle of Manhattan. Not so with Verizon.
I also think Cingular's customer service is absolutely HORRIBLE. Ever since my account was "migrated" from AT&T to Cingular (over 2 years ago), they still can never find my account record when I call in, which requires a 20-minute search and providing so much personal data, Cingular knows more about me than my mother. All this is done by someone who can barely speak English and can't do anything that veers away from their customer support script.
Plus, let's not forget that Cingular is one of the phone companies who willingly hands over phone records and other personal data to the government on ALL of their customers. Talk about breach of privacy! Apple could not have chosen a worse provider for their cool new phone. Tragic!