First off I am going to say that I thoroughly enjoyed reading the entire codex from cover to cover, with a slight hesitation and skipping of the dynasties. I did go back to read it, but for me it was the low point of the book.
I thought the book was well written, and the background and new fluff is exciting to read through. I know old timers that have been loyal to the necrons in the past still dislike the new fluff, but I really liked it. Background like the War in Heaven is great stuff, and ties into the other races well.
There was even a couple surprises that caught me off guard, like the message from Trazyn the Infinite to Inquisitor Valeria. Quite the deadly exchange that I will not ruin for future readers.
I have already fixed my ideas into several lists, and some of those ideas I will delve into in the coming days. In doing several list building exercises I have come to a few conclusions about the Necrons. One of which is; this not a MSU army where every slot of the Force Organization chart will be used. You have to design carefully and strategically.
Other surprises for me are the troop choices. I expected to want Immortals in my lists. Amazingly enough, I have began to like warriors over the Immortals. So I will tackle that first.