A masterpiece defenitely.
Like Jrmontero I played all D&D versions up until 3.5 and now play pathfinder among several other rpg systems.
And several tabletop games as well.
This game has just this unique feeling to it I haven't felt in any other and plus in a country where is almost impossible to get new players for anything or very difficult to convince anyone to play anything new, the ability to play solo is a big bonus.
I have a steady group that has been going at it weekly for nearly 5 months now and we haven't even delved into to the 2nd adventure path since we play with what we have.
So I want to add my thanks to those already previously stated in this post to all the developers and people responsible for putting out there and also those responsible for making it cross borders and an entire ocean ;)
Thank you!