This book was an interesting look at micro-organisms and although there is a lot of speculation and the author can't quite get out of the magazine article style that makes him physically describe at least some of the people he interviews, I can't help feel that this is what Gulp by Mary Roach should have been. I mean, he actually explains the whys and hows of fecal transplants instead of just pointing at this "gross" thing and saying it helps some people.
The narrator (Charlie Anson) wasn't bad either, although I did sometimes have to rewind a bit because I'd caught myself not paying enough attention. But that's more the subject matter than any narration failings.