very 'cool' (as in not warm)and a bit heavy or somber to me. They could add some warmth with art as has been suggested. But overall I like it, and I usually do not like modern very well.
The thing that bothers me about the books is that they are all laying on top of eachother. Now books can be all upright against eachother, or half and half, with some stacked on top and others stacked side to side, but never all just stacked on top of eachother! One of my nutty peeves.