First, I would like to preface this comment by saying that Jared Diamond is not an anthropologist nor is he an archaeologist. He's a bio-geographer who writes on a multitude of topics ranging from biology to archaeology to technology, most of which can be found synthesized in his books. While I don't agree with his conclusions, I have to commend him for his ability to bring all of these topics together in a way that's approachable and not overloaded with jargon.
Diamond's argument at it's core is that some societies have advanced and others haven't because of accidents of geography which have allowed some societies such as Eurasian (who's continent is oriented east-west) to develop food production and advance ahead of other societies such as African and American societies (both of who's continents are oriented north-south). This east-west orientation allowed for easier transport of food production as well as social complexity that gave these people a head start.
It sounds like a good argument and Diamond makes a great case for it using geographic, botanical, historical and even linguistic data to support his argument. Unfortunately much of his arguments center around broad generalizations of his points. Specifically, the argument over the new world falling due to germs and steel. This is true in many cases, but many groups had longs since disappeared by the time Europeans arrived. Even a thriving chiefdom like Moundville which was said to house thousands of inhabitants was nothing more than an acropolis when de Soto came through the south in the 1540s.
Many scholars have rebutted Diamond's claims much more eloquently than I could possibly hope to accomplish here. It seems to me though that if more academic and historical information were available in such a readable and approachable format as this, perhaps there would be more interest in these subjects aside from these few texts that make it into the mainstream and what is left in the academic world. To be honest, I think some academic writers could take a few hints from Diamond and his way with words.
All in all, this book is very recommendable. But like anything, it can't be taken at face value. Most of the research presented here is merely the tip of the iceberg.