I'm rooted and was having random reboots then I tried several different ROMs "stock" OTA update, PerfectStorm, BAMF 1.6.3, and all of them have given me random reboots. I've had at least 2 in the last 2 hours, and I say that because I happened to be using the phone when it rebooted. I suppose my next step is a factory reset and start all over again.
I'm in a non-LTE market, but I also had a couple of random reboots yesterday while I was using the Navigation to get me around Houston.
Hope VZW and HTC get they're isht together in a hurry!