I'm sticking with Sprint at least until 2014 when contracts are done and NV should be complete. Right now I get good 3G coverage in my area with some bldg penetrations issues at work sometimes. I don't have WiMax where I live and I can't use it at work since it won't work in my office so WiMax has become a non-issue for me. I use Wi-Fi @ home.
If I can't get usable LTE at home and work once NV is complete then it may be time to move on. With Sprints new pricing (i.e. removal of discounts and incentives), we all have to do our due diligence and check out the competition. The only thing that may make me hesitant is giving up AMAT, free Pick 3 on all lines and free N/W @ 5. Oh, I'm not a huge data hog so unlimited while nice won't be a huge retention factor.
P.S. If each carrier had the same price point, would you still be with Sprint?