We have been to Disney 4 times over the last four years (are here again to ring in 2012). Two years ago, we had a studio facing the Magic Kingdom (beautiful room on the north side of the lobby just under the Grand Villa). On New Year's Eve, we went over to the Magic Kingdom and had dinner at Liberty Tree. By 8:30, you couldn't get near the Castle and if you were in the front of the park trying to get to the back of the park, they were routing you behind the Plaza Restaurant into the parking lot and into Tomorrow Land. It proved to be too much for us so we headed back to our room around 10:00. We went up to the lounge at 11:00 figuring we would hang until the fireworks. We had a good time. There was a DJ out on the observation deck and servers bringing drinks around. There were also LOTS of people. Shortly before the countdown, we scurried back to our room, opened a bottle of champagne and welcomed in the New Year while watching the fireworks from our balcony. It is an evening I will always remember.
So, depending on what you are looking for, BLT can be a great place to be, but get a room facing the park for maximum effect. Especially if there is a gang of you.
This year we're back at Boardwalk and will do HS. Last year we did Epcot. Next year will probably be BLT again. Good luck with your decision.
~ David