I live in San Antonio, and I haven't seen much in the way of LTE at all. I had connection for about 5 minutes on the 13th at 1604 and 281 and for about 20 minutes yesterday at Bandera and 1604 but otherwise, nothing. I live and work downtown right in the middle of a bunch of towers, but I haven't had much luck. Hopefully, Sprint is still in the process of getting their towers online, and availability will improve over the next few days/weeks.
EDIT: I checked out sprint.com/coverage, and supposedly, LTE availability shouldn't be a problem. Maybe they haven't flipped the switch on the tower in the area.