update: OK, so I called sprint to ask what the deal was. Apparently LTE was disabled in the shipping config.
They had me do the data config (##3282#) and then edit. Enter MSL, then Advanced and check the box next to LTE to turn on.
We did not modify the 6 settings under Others | LTE APN Settings, but left it as "APN2 LTE internet (n.ispsn)"
It was active immediately and did not require a reboot, you just have to use the back arrow to get out to your desktop.
I ran speedtest here on the eastern fringe of the metro area and got 5.5Mbps down and 3.8Mbps up. I'm pretty happy with that as it's inside my house and I couldn't get WiMax on Evo 3D consistently until I went half a mile west even outdoors.