We have only stayed at BC once but we absolutely loved our room location and balcony. It wouldn't be for everyone but it was perfect for us. The room # is 4530 and it is about as far away from the lobby as you can get but the balcony is HUGE and has a great view of the IllumiNations fireworks. Just the high fireworks, mind you, but great view nonetheless.
The room is located on the Epcot side of the resort and under the eaves of the building and because of this situation the balcony is about 40 feet long - even wider than the room because it is the last room in the hall. It's also completely private since the eaves forms walls on either side of the balcony. We had easy access to a stairwell to get in and out of the resort and it was a very easy walk to and from Epcot which was perfect for us as we were there primarily for the Food & Wine Festival.
Like I said, this room would not be for everyone but if you want a really big, private balcony with a view of the IllumiNations fireworks and the closest possible proximity to Epcot, it's a great room. The only drawbacks to this location is the long walk to the lobby and boat dock.
The biggest drawback for me is that I'm afraid I'll never get DH to agree to stay here again since I can't guarantee him we'd get this room. LOL!
EDIT: Forgot to mention, this is a smoking room. DH and I are not smokers and the smell didn't bother us but we may not be as sensitive as others.