Ok so I must say this book sucked me in right away! It is very action packed and kept me wondering what was going on. Now for you Harry Potter fan's Nicholas Flamel created the Sorcerer's Stone, and the fact it causes the person to be immortal...however you won't see Dumbledore appear. The author also tied in some of the different people of the Ancient worlds and mythological worlds. It did take me a bit to read, but that is only because I was only reading it at work. It does end on a cliffhanger, but the next book is out already, which I am thankful for..so I don't have to wait for it to come out :-p
I will say that some may have an issue with the narration of the book though. It jumps from one character being the narrator to the next. This doesn't bother me, but I know some people don't like it. Otherwise I don't think this book has too much of a downfall.
So overall I give it an EXCELLENT rating!