I read this aloud to my 15-year old son, until I finally told him that I couldn't read it any longer. He finds it much more difficult to stop a book once you've started, and I find it painful to continue to read, particularly out loud (which is slower), if you're not enjoying the experience. We made it to 65% through, and he has said he would probably just finish it on his own. Note that he has not made any effort to do this, so maybe he didn't like it that much either. 
 I've heard this described as an "R-rated Harry Potter" (sorry I cannot remember the source!), and that is the most accurate four word description I would give it too. A guy finds his way to a school for magicians, where he takes a test to enter, passes, and then BAM, he's finished with all several years of school right around the halfway point in the book. 
 I didn't care for the timing, the characters I found underwhelming, and mostly I didn't want to hear any more about Fillory. 
 I am willing to give the TV series a try; I might be more entertained by that medium.