Great to hear they're testing LTE; I know Sprint's CEO has specifically stated that they're not married to WiMax, by any stretch of the imagination.
Considering the bandwidth advantage of LTE (and the much bigger once, latency...which is horrid on WiMax, but like DSL/cable on LTE), I can't see WiMax winning, even if it has a 1-2 year advantage.
I've heard rumors (don't know if it's true) that WiMax equipment can handle LTE with a simple software upgrade...hopefully, that's true.