It's written cleanly and documented well but it falls down:
Fast and lightweight - I would say the 'fast' part of this is inaccurate. Sure when visiting a page that has been cached it will be quick but for anyone being the first person on that page or the first person on it after 8 hours it is slllooooowww. Lose 1 star.
Requires Apache - no where on the page did it state apache was a necessity. Anyone using NGINX good luck.
Lose 1 star.
If your server is apache based and speed doesn't bother you then it is quick to install and get running and a worthy purchase at the correct price.