It's also, from what I understand, generally considered "bunk" by people who know the field.
My mother has a degree in Archaeology and considers Jared Diamond fairly suspect (Guns, Germs and Steel in particular). Apparently he cites some articles/books that have various problems (methodology, factual errors, etc.) These problems were well known at the time that he was writing.
I would encourage anyone who reads it to also read reviews/critiques by qualified people.
Read the book during a comparative politics class, so yes I have read a fair number of critical articles. That being said I have also read a fair number of scholarly articles in support of the angle that Jared Diamond was getting at. No one is right always, that is why you must be objective and read critical peer reviewed articles.