I saw it in IMAX 3D because it was the only option for me and made my recommendation as opposed to a 2D viewing. If you've got a better 3D option then certainly go for it. Also, it's not so much because the 3D is "so phenomenal" or anything like that, but this, IMO, is one true example of how it enhanced the movie. Because the movie is "thin" in terms of story line (not meant as a bad thing btw), you truly relying on the visual more than anything else because there's only so much the actors can do. In this case I feel the 3D, particularly in a solar environment, quite successfully pulled you into the situation more. I again disclose that I've never seen Avatar in 3D so the best 3D representation that I've seen was The Avengers. Regardless, every movie that I've seen in 3D will lose nothing upon seeing it in 2D. Gravity will not have the same effect in 2D, nor will it have the same effect on a television screen. Or at least, not one under, say 60".
On another topic, I think you'd be hard pressed to argue how well Sandra Bullock did with this character and simply further demonstrates that she's matured and hit her acting stride. Given such, do you think this is an award winning performance from Sandra Bullock?