Excellent book - 23 bite-size adventures for a whole bunch of different party experience levels (and add or take away a few monsters to push up or down the difficulty level). If you are trying to find a big bang to end a chapter of your game, this would be a great purchase.
Each lair is imaginative, bold, well-thought through, and (unsurprisingly, considering it comes from the author of 'The Lazy DM'), easy to use.
The pdf version comes with VTT maps and a separate pdf with all the monster stat blocks in it - very convenient. I also got the hard-back version, which is impressive quality, considering it's print on demand and half the price of a WOTC book. I use the printed version to pick and read the adventure and the pdfs to run it.
It's got bespoke art pieces for every adventure, which really adds to the whole thing, however, one suggestion to authors would be to have jpgs of all the art as a separate download so we can show it to the players!
So... when's Fantastic Lairs 2 coming out?