Saw ATTLG yesterday in IMAX 3D and I have to say that I loved the film. I thought it was great fun and super imaginative with tons of great performances from the amazing cast.
As for the 3D, I rather enjoyed it. It is true that pop-puts are scarce but, on the other hand, the image was always very deep, like a window into another world.
[Show spoiler]The "sea of time" sequences specially stand out.
The image was also very rich in layers. One of the things I noticed was that while in the first film almost everything CG seemed to have been rendered in native 3D leaving the conversion almost strictly to the live-action shots and plates, this time around even CG heavy moments seemed to have been completely converted into the stereoscopic format.