I met Ambrose once years ago, he was very cool. Had a mind that just shone like a lighthouse, when he talked his intelligence and depth of knowledge were readily apparent.
The only small criticism I have of him is that he seemed to think that Eisenhower could do no wrong. He really idolized Ike, but you know, its a small, really tiny, fault in the big picture, and its just my opinion. I read all his world war two series books, they were great. If you only read one, read D-Day, its the best imho.