I became a Pacific Bell Wireless (now Cingular) customer in October of 1998. I chose PBW because I'd heard good things about their coverage. Also, I'd heard that the call quality was clear, with very few dropped calls. A big part of why I chose PBW is also due to the fact that they are a GSM carrier so switching phones is no hassle.
I purchased a Motorola StarTAC phone and a $29.99 plan that included 100 weekday minutes and 500 weekend. This was before Pacbell switched to nights and weekends so the 100 weekday minutes is exactly that. You get 100 minutes from 12:00AM Monday to 11:59 or so Friday, then Saturday and Sunday you get the 500 weekend minutes. This plan wasn't close to being the best value available at the time, but I was convinced that PBW's quality and coverage was a good enough reason to choose them instead of the competition (CellOne which is now ATTWireless, GTE now Verizon, and Sprint).
Aside from hardware problems (my StarTAC needed a BIOS update), I've had nothing but good service from PBW. Calls are clear and it isn't hard to go somewhere where the signal is strong if necessary. I've since upgraded my handset to a Nokia 8890 and it performs just as well as my other phone.
Aside from the good coverage, what I like about PBW is their rate plans. They are pretty good at staying competitive and upgrade their rate plans frequently. I started off with $30 for 100 minutes on the weekdays and 500 on the weekend. I've since upgraded several times and now I currently get 300 minutes peak and unlimited nights and weekends with free domestic long distance and text messaging for $40 or so (the Cingular 300 plan). The only caveat in upgrading rate plans is that PBW may require you to restart your one year contract in certain instances. This can be somewhat of a nuisance but it's quite easy to haggle with the customer service rep and get your way.
I'd definitely recommend PBW (Cingular now) to anyone looking for good, reliable wireless coverage at a value. I live in Berkeley and I get excellent coverage here as well as in Oakland and San Francisco. The only trouble I've had is in San Jose during rush hour, but that's understandable as everyone's on their phones in traffic.

Recommended: Yes