I purchased the POD and am happy with the results. There are a few pages that are a little light, but overall it is more than good enough to read.
The only minor issue with the print version is the order of the booklets. The Explorer's Manual is described as the first one to read and has the list within its pages- but one reading this will not find that out until they get to the fourth booklet within the print version. I honestly don't care as the information it provides isn't vital to understanding and enjoying the product as a whole. Just to warn others who do by the POD option.
As for the contents, there are nine booklets written by four authors in nine different styles- each has a different fictional author (Elminster does the Explorer's Manual only). Some are better than others, but none of them are remotely bad. They cover a lot of different habitats and most of it can easily be applied to other settings. Some of them cover the human inhabitants a bit too much in my opinion, but then the intelligent races do have an important impact on the ecology and cultural interactions of a given region. Overall I think it should be useful for anyone wanting to make their monsters more interesting.