Nextel service is pretty brutal up in the Northeast. Its great as long as you're near an Interstate or major city. After that, it is a little rough.
My Dad is a salesman and had Verizon. Their company decided to save some money and switch to Nextel. The service was significantly worse! Actually, he's finally accepted the change, and in some cases doesn't mind it because people can no longer reach him at home. LOL.
As for Verizon customer service, I've always had excellent experience. However, this may be due to my long service history with them (over 5 years). I'm sure with any major company, everyone hears about the horror stories. As for me, I've received significant discounts on cell phones (got a StarTac back in the day for $50 when it retailed for $200), never have a problem with excessive charges, and they've always been pleasant to me. Heck, if I'm ever disconnected while talking to them, they call me back!