I saw this Friday night in 48fps IMAX 3D (supposedly with Dolby Atmos sound, but the film didn't seem to take advantage of it at all.)
Based on what reviews I saw beforehand, I expected the film to feel longer than it did. It didn't feel
like almost three hours, but it was definitely erratically paced. It was much lighter than the LOTR films, which I think everybody has pointed out. Some of the action scenes went on too long, and the bit that probably irked me the most was when Bilbo fell down the cracks in the mountain, and apparently only suffered a few scrapes and bruises. Completely absurd. Or, for that matter, when Thorin was picked up in the warg's mouth, yet survived (with a little help from Gandalf.) Hello, puncture wounds? Even if Gandalf revived him (which seems to be the implication), unless he also healed the wounds, Thorin can look forward to dying of sepsis in short order. There's fantasy violence and then there's complete nonsense.
That said, I did enjoy it, and it was nice to return to Middle-Earth. It certainly wasn't on the level of the LOTR films, but I didn't really expect it to be, either.
As for the 48fps, most of the time I didn't notice it. However, a lot of the movements of the actors appeared really fast
, and that was quite noticeable. It took some getting used to, but I suspect if I see another film or two in this format, I won't really notice it anymore.
I think all the criticism of the 48fps format is silly, though.
I will say that the 3D didn't add much. The higher frame rate (and IMAX projection) made a lot more difference, for my money.