I think I had my first real "uncanny valley" moment thanks to The Hobbit. I went in wanting to like it, fully on-board, but I now wish I'd seen it in 2D. The image was so close to reality, but just "off" enough to be weird and confusing. The extra work my brain had to do to pay attention to the story and also process all the extra motion and my immediate negative reaction to it, it was exhausting!

The extra "immersion" provided by the higher frame rate was uncomfortable, "too real" in a way that broke the spell. Real people magically become other characters, other creatures, at 24 fps. At 48 fps, they remain real people in costumes.

When an actor moved quickly, the lack of motion blur made their actions seem sped up. I'm certain that everyone in our theater noticed it. It was very distracting.

The HFR worked on some of the slower stuff, particularly with Gollum, and some of the sweeping vistas. The camera work in Bag End felt particularly rich and believable. But actors working against green screen looked awful in higher framerate. It looks like something filmed for basic cable. It's not cinematic.