Read the early reviews. PJ showed the first 48fps trailers at some event recently, and the response was almost all negative regarding the "look" of the film. All the trailers making the rounds now are 24fps, and PJ is saying that that's because most theaters cannot do 48fps. While that's true, it's also true that most modern theaters use digital projection now anyways, and The Hobbit movies would be shot at 48fps, converted to digital, and projected that way. So it's spin, damage control.
That's the extremely cynical side. The less cynical point out that ultimately, increased frame rate *should* look better overall, and it's just that our eyes and brains have become accustomed to the look of 24fps and associate it with movies. Similarly, our brains associate the hyperrealism of 48fps with video and TV and stuff we know inherently is fake.
Example: The black and white footage in DT's Metropolis Live in NY DVD. It's supposed to be memories, less realistic because it's black and white, reminiscent of an old movie. But it doesn't look like that at all; it just looks like black and white video. IMO, Mike made a huge blunder by not actually shooting those scenes on black-and-white film. The effect would have been 100 times better. It would've "felt" right. Instead, the black and white video takes you out of the moment, not into it.
Anyway, the optimistic say that we will eventually get used to film at 48fps. It's just that we're used to a certain look. PJ says 48fps is the wave of the future, and someone has to lead the way. But those "red" cameras are really expensive, and the results they give are getting mixed reviews at best. We shall see.