Just a personal 48FPS testimonial here...

For some reason I found myself at an IATSE event. IATSE is a union for motion picture professionals. At the end, they projected a scene, once in 24fps, the second time in 48fps.

48fps looked "real" to my eyes, insomuch as it looked how I imagine it would've looked to have been in the room.

Unfortunately, that's not the look I like in films and movies. It truly looked like a soap opera.

There's a chance that 30 minutes into the Hobbit, peoples eyes will acclimate, and you'll forget, but I think those initial scenes are going to be a bit of a disappointment.