I'm 200 pages into it and loving it. I wasn't sold on the time-travel idea, in fact I was expecting this to be a complete dud. Now I'm completely taken aback by how much I'm enjoying it, and how well written it is. The highlight so far was when I read the scenes that feature characters from IT, I felt very nostalgic and emotional revisiting that setting, I felt as if I was revisiting the person I was when I read that book.
As always, I am in utter admiration of this man.