I'd suggest you stick with Sprint, since they have far better coverage on their 3G AND WiMaX coverage. They'll also implementing 4G LTE and your city maybe soon.
Overall, once 4G LTE is implemented, you can get ONE PLAN with access to their 3 data network: 3G/WiMAX/LTE. They actually sell a hotspot that can accept all 3 data types.
I have Clear since the day of iSpot and I even still have my grandfathered plan ($25, unlimited data, 6 Mbps down). However, one thing I noticed is that Clear 4G doesn't work very well inside a building. I can go to places that is supposedly next to their tower and once I am inside a building.. ZERO coverage. My iSpot device manual actually recommend that I put the device NEXT to a windows (yeah right..).
And did I mention they don't have as much coverage as Sprint?
Just my 2 cents..