This PDF guide is... exactly what it says it is, but I'm not sure it should be sold by the writers, instead of being given away for free. You are essentially paying for the art and type facing, as the information inside is, while useful, brief. No rules, no extra options, just what is, and what is not compatible from one setting to the other. And honestly, most of that information is pretty common sense. So unless you are looking for more story fluff, or are a GM who owns both games, I can't see this being very useful.