Watched this Saturday on my 2010 Samsung 3D plasma. I'm not at all familiar with the character of Tin Tin (never even heard of him until this came out) but I found the movie entertaining and it played out a lot like what I would have liked from a Young Indiana Jones story - rollicking adventure, wild and improbable stunts, and an interesting mystery.
The quality of the CG was really amazing; take out the deliberately exaggerated characters and the environments were practically photo-realistic. I can only imagine what will be possible with CG movies in 10 years time; overpaid, aging flesh and blood actors could even become an endangered species.
In terms of the 3D, I experienced a nice sense of depth most of the time. Dark scenes seemed pretty flat however and the "glasses off" test showed that there was a distinct absence of double images when things got darker. The tradeoff was that ghosting was all but non-existent even on my older rig. There wasn't much in the way of popouts, just debris and the occasional cane or sword; stuff swiped towards the screen moved too fast for the eye to really focus in on the illusion. The movie had a 2.35:1 aspect ratio and this further impacted the sense of depth on my TV; its too bad Spielberg didn't have it rendered at 1.78:1 which is closer to the aspect ratio most people can enjoy at home with HDTVs.
Overall a fun, watchable movie with some amazing CG, decent replay value and good (but not great) 3D in my opinion.