John Rateliff did a 3-part review of An Unexpected Journey, which was quite positive from what I remember. Here's his considerably shorter Desolation review. He makes good points about trying to appease movie critics chomping for more action, and Tolkien fans saying there wasn't enough of The Hobbit, the barrel-riding scene, and the dwarves trying to kill Smaug.
http://sacnoths.blogspot.de/2013/12/the-desolation.html