I've really enjoyed reading the Lamentations of the Flame Princess Weird Fantasy Role-Playing game so far. It's a new, traditional style RPG, based on the solid foundation of 1st edition RPGs you're likely familiar with already. However, unlike other "retro clones" which can have a sameness and vanilla fantasy quality to them, this game has a strong authorial voice and the implied setting is much darker and more "weird fantasy" than most fantasy RPGs.
What I particularly enjoyed about LotFPWFRPG (that's some acronym) was seeing the new ideas being brought to a traditional game. It's these interesting additions and changes that make me most interested in reading more of the book - where other "old school" products tend to just get used as reference and are largely left unread. The unified d6 based skill system, and accompanying character sheet design was a nice surprise, as was the Choose Your Own Adventure style tutorial adventure to teach new (and old) players how the game works. The LotFP take on the Thief -- the Specialist class -- is also nicely done. I can see many of these ideas making their way into other Traditional RPG games in the near future.
The PDFs are not the same layout as what you'd get in the boxed set, and I have somewhat mixed feelings about that. If you're planning on just using them on the screen then you'll be very happy with them. They're formatted in a single column so they're much easier to read with a landscape format monitor. However, if you wanted to print them or view them on an iPad or portrait format monitor, while quite serviceable they're not as nice as what you'd find in print.
Having said that the PDFs are only $12.50 which is a very reasonable price for so much gaming material. The artwork that accompanies them is also much higher quality than many games you'll find at that price point as well.
Overall I'd highly recommend this game to anyone who's taste in RPGs tends towards the rules light and setting dark.