We were fortunate enough to be able to sneak two editors into this movie showing and consequently can share with you a pair of (contrasting) perspectives on the experience. Sat in amongst the sweet spots near the middle of the theater, Richard Lai found the whole thing a blast, describing the picture as terrifically sharp and remarking on the fact he experienced no eye fatigue even after the full 103 minute runtime of the film (which was padded out with 3D footage from the World Cup and some other fluff).
This hapless scribe, on the other hand, managed to be late enough to garner a seat on the very edge of the audience, getting to savor 3D from a wide angle. And you know what? It kinda sucked. Although objects in the foreground retained the aforementioned sharpness, the left- and right-eye images were discernibly delineated on background or more distant objects, and the effectively incomplete stereoscopic effect served to diminish rather than enhance your absorption into the movie. Just to get all the bile out of our system, we should also mention that there's a noticeable dropoff in brightness when you pop the RealD 3D glasses on relative to what the screen emits -- it seems to be accounted for, as we certainly can't complain about the film lacking vibrancy or color accuracy, but might be something to bear in mind.
On the whole, though, we have to say we came out of the cinema impressed. Sony's implementation of 3D using these 4K-capable projectors is manifestly better than what we've experienced so far -- eye strain seems to have been entirely nullified and sharpness is tangibly superior to what competing technologies are currently able to deliver. So long as you bear in mind that 3D comes with significantly narrower (ideal) viewing angles than the conventional stuff, we reckon this is the best choice for enjoying it.
We're not going to broach the hot question of whether or not 3D is worth it -- that is most probably a judgment to be made in person -- but we will say that it didn't seem to enhance Toy Story 3 on a consistent basis. There were some highlight moments where 3D really took the action up a notch, but the film's immersion mostly felt on par with what its 2D version would have delivered. Will "made for 3D" movies push the currently sporadic utility of the technology into something more robust? Maybe. All we know is that there'd be some 4K voodoo thrown in there one way or another. We've now gotten our first taste of the stuff, and even though it ain't perfect, it's the best damn 3D we've assayed so far.