Saw Gravity in 3D, because if I didn't, I'd be constantly wondering if I had missed out on something grand.
That is the last time I follow the herd.
If Avatar and Gravity are examples of how 3D is best used: f**k it. It's a waste of money (and probably your eyes).
There was nothing different about Gravity to any other 3D film, other than that, as most visuals were backed by the blackness of space, the effect was more pronounced.
It doubt it made the movie any more or less impressive than if it had been seen in 2D.
I will say, though, that it'd be worth watching on an IMAX screen. Just seems made for that.