I've had a 55UT50 for about 2 weeks, and I am exchanging it for a 55ST50 (found open box at BestBuy for $899) for the anti-glare filter. Since I've had a 42" Panasonic plasma for 10 years, I though I could deal with the UT50's glare; but it's worse than my old one. Even my wife notices.
If you can place the UT50 in a light controlled room, then it is hands-down the best bang-for-the-buck set out there.
I just got back from a bestbuy that had the ST50 open box. They said it was just over a grand and they would not budge.