I've always been particular fond of ecologies, so when I saw an ecology to the ratfolk, I had to pick it up. I love wererats, but how are the ratfolk different from these well-known lycanthropes? Well, for one, the ratfolk only has one shape, and since there are more of them (a lot, in fact) they can build rather large and complex societies.
Lets look at the guide to ratfolk. This presents us with a short history of ratfolk (which is large unknown, sadly), a description of the three different ratfolk variants (ratlings, ratfolk and nezumi - the biggest difference between these are the size and whether or not their walk on two or four feet), a description of the mindset and society of the ratfolk (which I could have been without since each race gets its own walkthrough later on), a short section on enemies and allies (note that ratfolk only really trusts drows!).
Next up is the meat of the product, the three playable races. They are pretty straightforward, but a little underpowered, if you ask me. I am also not sure that I agree with the various ability score bonuses/penalties. I find it really hard to believe that ratfolk are weaker physically than ratlings, who weighs between 15-25 pounds. The four alternative racial traits are pretty cool and useful and I think two of these should have been part of the original traits (prehensile tail and scent). This meaty section ends with a couple of mundane items and some feats, 4 to be precise. Of these, I really like the pack fighter.
Lastly, the GM gets a single monster called a rat ogre. I really liked this creature, which is created naturally, as part of the mutation process. I can easily see how these stupid brutes will be used in the ratfolk society.
Overall, I like the material found within this pdf. You get a lot of material for your $2, which is really nice. However, I would probably need to make a couple of adjustments if I decided to use the playable races, but with the excellent alternate racial traits, I think this could easily be done. My biggest problem with this pdf is the layout, it could really use another round of proofreading, also, when printing, the dark (purple) corners become really dark making it hard to read some of the text. This is a little annoying. Lastly, I want to mention the artwork.... which is excellent and of really high quality.
[4 of 5 Stars!]