I sat down and read this at my local bookstore today, cover to cover. It is interesting, and worth a read, if you are interested in 4e, which I am. However, it is just a preview for Fourth Edition. Why people would pay for a $20 preview, I just can't understand.
Don't buy this. Flip through it at the bookstore, if you must, but don't spend money on this.
I absolutely love this adventure. It doesn't hurt that it's free to download either.
It is perfectly written, has some really great art, and excellent maps as well. I'm a huge sucker for maps. If all the Game Mastery line is up to this standard, I'll be buying every one you guys decide to write.
I highly recommend DM's check this out and jump on board the new campaign setting that this module is introducing that will be featured in Pathfinder and other GameMastery modules. It seems very interesting to me and I can't wait to see more. Keep up the good work guys.