Yep, gotta agree with digi. It depends on your area. For me, sprint vs vzw is a push as far as coverage does regarding voice and data coverage.
However at work, the contract is with Verizon. I had a verizon phone from work for about 6 months. Data coverage while it existed was total garbage as far as speeds go. Kind of made the phone useless for emails even.
I turned in my work phone, got a personal sprint phone, night and day difference for me. No difference in voice coverage or data coverage, but the sprint network for data near me is much faster. Top that off with a 1 to 1 comparison of features and prices and sprint wins easily for me. Even when I was out on the west coast in traveling through the rocky mountains this summer, I never once had any coverage issues with sprint and never failed to pull a reliable data connection while roaming.
There is not one carrier that can claim to be the best in all markets.