"The Desolation of Smaug" works better than the first installation of Peter Jackson's "The Hobbit". It's action-packed (I was worried that I might snooze since I saw it at 9:40pm) and the addition of Legolas and Tauriel, while not in the book, work much better than the "Great White Orc" villain in the first movie. Tauriel may replace Arwen as my favorite "Hellooooo, Elf" (as spoken by Yakko and Wakko Warner) character.
I also feel that the simultaneous backstory of Dol Guldur, while not fleshed out in the book of "The Hobbit", makes this fit in nicely with Jackson's "Lord of the Rings" movies.
I wish the first movie was as good as this one. It's worth the $10+ to see this in 3D as it really draws you into Middle Earth.
Regarding the end, well, they want you back in the theater next year, now don't they?
Oh, and I missed the Doctor Who connection in the two movies until I spotted a familiar name in the credits.