Maybe it was just the cinema I saw it in, but I thought the cons of the 3D outweighed the pro's. The colours and overall brightness seemed somewhat dull with the glasses on and the image was quite soft, almost out of focus. Admittedly, I was on a wing seat (all the good seating was taken by the time I got in), and so maybe a direct front on viewing angle makes for a much better experience?
Soundwise I think the soundtrack would be great, but the cinema didn't do it justice. I think you guys in the US have much nicer cinema's - especially the D-Box enabled ones. Even the Sydney IMAX's sound isn't really impressive at all. Haven't noticed any great sounding cinema's in Sydney which is what led me to building my HT a few years ago.
I can't wait to get it on Blu-ray though