I got to see the Hobbit yesterday in full-fledged 3D, 48 FPS mode.  Since they split the novel into 3 parts, I'll do the same with this discussion.

1)  3D, 48FPS - I think I would have been happier with the movie if I had seen it in 2D rather than 3D.  In the past I've found 3D films to be distracting and artificial for the most part, mostly due to the planar way the 3D is constructed (at least, that's my term for the way they seem to have foreground elements that are distinct from midground elements that are distinct from background - almost like a diorama).  While elements have their own depth, they are separate from the ones around them.  There were a couple of spectacular landscape shots where this wasn't the case, but too many more where even things like people walking on a mountain ridge looked like they were done using CGI even when you know they weren't.  I don't know if this problem was enhanced by the 48 frames per second or hidden to some extent.  Unfortunately, I don't think there is a 2D version that also has the 48 frames per second, so I don't think I'll have a chance to comment on that separate from the 3D.  I do know that I will probably try to avoid 3D for the foreseeable future since this was probably the best that can be done and I still found it distracting. 

2)  Issues - Before I get on to all the good things about the movie, I figure I'll throw in the other negatives (which will also mean that I leave everyone with the good parts active in their thoughts).  I suppose the first and biggest issue is that this isn't Lord of the Rings.  A huge set of expectations were inevitably built up because it was made by the same people, writtem (mostly) by the same people, shot in the same place and featured many of the same actors.  Originally, Peter Jackson and crew were only going to be producing and helping write the film, partly (I believe) in the hopes that a different director would give the movies a different style and feel.  Unfortunately, circumstances made this plan fall through.  I think the original plan/reasoning was correct and valid.  This is not to saying anything negative about Jackson as a director.  It is merely my feeling that the film would have been better served not looking and feeling so much like Lord of the Rings did.  Along these lines, I also found the many pieces that harkened back (homage sounds like the wrong word but is the only one I can think of that is accurate) to the LotR films distracting (the angry Gandalf effect in Bag End, the way Bilbo first puts on the ring, the similarities between the Goblin lair and Isengard, etc.).

Other issues are more inherent in the source material and how to bring it to life.  For instance, there is no way to avoid having a main party that includes 12 dwarves.  While they all look different, the only one I could identify consistently was Thorin; the rest blurred into a group of "the others."  Also, in padding out the novel to 3 films, there seemed to be a tendency to take their time letting scenes and plotlines evolve.  So some parts seemed to be slow (which is different than dragging, which has you glancing at your watch every 30 seconds).  In addition, there is a lot of exposition that is needed to set up the added parts, especially in regards to the Necromancer, which will undoubtedly pay off more in the second and/or third movies (I haven't read the book in many years, but don't remember the white orc at all - this was another piece that had a lot of exposition and continual reference).  And, Bilbo finding the ring and Gollum's reaction to losing it were slightly different than in Fellowship.

3)  The Good Stuff - First of all, this is a gorgeous movie.  Mr. Jackson has a definite eye when it comes to settings, landscapes, and showing off the natural wonder of New Zealand.  Second, the casting is really good.  Richard Armitage as Thorin has the gravitas needed of a driven warrior leader.  The eleven other dwarves (even though I couldn't place name to face) were distinct and their own person.  The other returning characters are distinct in some ways from the those seen in Lord of the Rings.  Martin Freeman as Bilbo is reminiscent of how you would think Ian Holm's over version would have been when younger, but at the same time is very much his own.  Ian McKellen's Gandalf doesn't quite have the weight of the world on his shoulders yet.  Even Andy Serkis' Gollum is somewhat happier, not having the 60 years of ring withdrawal to drive him even crazier.  Finally, the framework for the rest of the story is definitely there, so I (at least) can still eagerly look forward to what the next two movies will bring.