I also picked up Sprint LTE today in Marin, in Terra Linda, a few miles west of the 101. (Download 8-10mbps) Back to 3G in downtown San Rafael, but then had LTE again in Corte Madera, similar speeds.
For a little while, I was also getting an upload speed faster than download! 10 mbps
Looks like they're testing towers, prior to official rollout.