^ I'm curious as to why you read Zero Sum Game before Rough Beasts of Empire, since, chronologically, they occur in reverse order (RBoE before ZSG).
I actually started RBoE first. One day I took my car in for oil change/smog and walked to a bookstore to kill time and bought Zero Sum Game. I was over 100 pages into ZSG when I got my car back so I just finished it first. Now I'm reading the first Vanguard book.