switching cell phone services

Ok, I’ve been searching all over the web and have yet to find a definate answer. Which cell phone service offers the best plans and coverage areas. I am interested in switching plans however I want to be sure that if I pay less for another service (I am currently using verizon, which is expensive), I will be able to receive the same high quality service. Service is my number one concern. As well, phone selection is always a plus. I hear that cingular and sprint are quite crappy. Anyone have any recomendations or links where I can find the best coverage and service?

I am pretty much comparing Verizon vs. Voicestream

Thanks.

-Jeremy