It's a bit hard to tell my opinion about this book. I loved all the characters (and yup they're a lot!) and many scenes are great. The writing is flawless (even if sometimes even over my pay grade - I'm not a native English speaker and this has been the hardest book I've read this year) and every place, every action was 100% King style - that I adore. But I didn't like too much the plot itself. Not the starting idea (that was cool) - but the "reason" - the male/female thing is ok, but it gets too much fairytale-ish - that fits well so much with the other stuff related to shrinks & bazooka shooting - at least for me.
Not too oddly this didn't prevent me to like the book - because everything else was good - the subplots (the characters live action) were compelling and at the end, the Why is not the most important feature when the What is page turning and when the people in the book seems so real that you feel sorry for some of them when things get crazy as they get.