It's good, but not great. The concept of delving into the hell dimension/contruct is great, but when you get there the place really is pretty nice compared to most ruins. There's an ominous guardian, that doesn't actually guard anything. And he suggests a terrible fate for those who escape hell, that never is mentioned again and seems to have been forgotten by the writers. same goes for the sounds of screams which emenate from the entrance portal, which don't make any sense considering what you find inside. And there's a big boss, who never actually shows up and there is actually no reason to go anywhere near it. And other than that just some pretty tame corridors and clean and friendly hard light fellas to round it out.

Would have benefitted greatly from a watching of Event Horizon, or at least The Gate. That being said, if you don't mind doing some re-writing and throwing in a lot more flavor, this makes a pretty nice base for an adventure. It's a cool location, and a real fun concept.

This is a pretty good sourcebook. Here are some pros and cons:

Pro: There is a fantastic selection of mutations in here, way more fun than the original book. Excellent additions also in character descriptions and foci, and some provocative new creatures. Fun new cyphers and oddities, very weird ones. By way of example, my players were both annoyed and pleased with the antler that you stab into yourself to become poisonous jelly that heals back lost limbs.

Con: Rusthaven itself is cool, but feels like a fairly empty place. Only one really neat feature to it. The adventure that comes with the book is good, but kind of falls apart at the end as there is really only one choice for the characters to make and not much in the way of puzzles to figure out.

The art is sometimes great, sometimes so so. Overall, I found the pdf version of this to be a good buy.

As soon as I bought this sourcebook, I began to integrate Rusthaven into my campaign, so that should say that I do recommend it.