I've been officially with Verizon since June of 2009. I originally had Alltel since January of 2005, but of course Verizon bought Alltel. And I have had my Storm since June, when I renewed my contract, and loved it ever since.
Since 1992, when they were "Ameritech" here in Illnois, and I got a BEEPER from them. Then I had one of those nifty phones that came with a giant gel pack battery and connected to the cigarette lighter in the car.
I have no intention of ever switching...I have been with them for 17 years for a reason. In my experience, the customer service has always been excellent, any problems are resolved professionally and promptly, and the coverage is unbeatable. Plus I get a new phone every year.