I was feeling the same way. For me, I want to go with what is good NOW, and has a proven track record. If Sprint actually does get its act together, you could always switch back in the future (assuming they don't eventually kill unlimited data too).
Agree with you here... I have Verizon LTE on my iPad and the coverage and speeds have been excellent. I'm not wed to any particular carrier, because they all have their strengths and weaknesses.