I bought the book the other day, and while i havent read every single page yet, its a bit meh..
Too many poor/boring encounters (especially level 3.. minotaurs, minotaurs and more minotaurs)
Also, it seems very much like Undermountain Light.. Ie the original one was deadly. If it had a 18 rating, this one would more be a PG-13 or something.
All in all, i felt that I wasted my money. For the record I own most of WotC books that arent campaign specific, and i rarely feel i waste my money that much.
And Halaster blew a spell, so to speak