I first saw this movie at a supposed IMAX cinema in NY Times Square. The sound was appalling and the screen was no more IMAX than fly! One of the speakers on the right of the auditorium was so soft it was as if it wasn't there. So I was delighted to find that not only was this in 3D but also in 7.1 surround sound. This is by far the best blu-ray I have bought so far - and lets face it, the studios have a lot to answer to regarding the release of Blu-ray 3D movies - whilst every blockbuster is released in the cinema in 3D only a few are being released in 3D on Blu-ray. Anyway all those reading this will already know this - Play.com should by chastised for continually advertising Avatar Blu-rays under 3D (although I see they now have a heads up system for when the real thing is released (At Last))!
This movie has not got not the best ever script but the effects are really amazing in 3D and the pumping soundtrack has to be heard in 7.1 - absolutely terrific. I really enjoyed it and it has now become my 3D "demo" disk. (Anybody remember Jeff Wayne's "War of the Worlds" "LP" being the audiofile demo in the 70s - similar reason!). You have to get this for the superlative vision and the audio - and movie is good too!
PS. I note that Disney seems to be releasing most of it's 3D Blu-rays in 7.1 sound!