I wouldn't recommend the OTA either, but to make it sound as if every single thunderbolt out there has a reboot problem with the OTA is way over exaggerating the issue. Just like everything else on the internet, if you have something that is working, you won't take the time to post about it. Have one small problem however, and you will spread the word to every Tom **** and Harry that will listen.
Personally I'm glad I updated mine, because it slightly improved the battery life. I was aware of the reboot issues before i updated, but I have not had any problem (there's some big threads where lots of people agree). My plan was that I would root the phone and install a custom rom if I ran into problems, but that hasn't been the case.
Coming from someone who did the OTA, and had it cause reboots, I still say DO IT!
You are still under your 14 days! Do it, and if it doesn't cause any issues, AWESOME! If it does cause issues, return the phone and get something else, or try another NEW Thunderbolt since within 14 days you get a new and not a refurb.