After having tried Cingular's EDGE and Verizon's EVDO our company went for Sprint's EVDO. The decision had something to do with the fact that they were a client of ours and spent some 10M w/us. But the bulk of it had to do with the fact that just recently Sprint surpassed Verizon's EVDO coverage. Also Sprint offered us a much better deal than Verizon, which included heavily discounted Merlin S620 cards.
From a user's prospective, Sprint is way faster than Verizon, especially in low coverage areas. Where Verizon's speed would crawl, for the same signal strenth Sprint would easily mantain a much higher speed. From an end user support prospective, I love Sprint's connection software. Clear, clean and so damn straight forward.
I don't like Sprint when it comes to private consumer products. Their practices and contracts are similar to a dictatorship. But, as much as I hate to say it... get Sprint! And this is coming from a hardcore GSM fanatic who changes phones every 6 months.