Verdict: it was fun, and gorgeously filmed.
Jackson had to try to make the interior changes in Bilbo dramatic, which made for somewhat uncharacteristic displays of courage. But he got the riddle sequence just right. The dwarves' comic relief isn't needed when there hasn't been any tension to relieve just yet. On the other hand the integration of parallel material (e.g. who was the Necromancer) to tie in with LOTR works fine. The goblins seem uncharacteristically hapless on their own bridges--which could have been finessed if the audience had been shown earlier just how strong dwarves were. (And the mountain creatures should not have been anthropomorphic!)
Still, a good time was had by all, and I have no problem recommending it.
I look forward to the eventual release of a director's cut, which should be shorter.