Light and flexible and fun. You can use it with many different genres, personally I think it leans a little to the light and humourous, but I ran a medium-serious supers game with it online. The PDF is formatted very nicely and the text is good, plus there are a ton of (mostly also free) resources (but if you like this, you'll love the Risus Companion, a 64 page supplement to this 6 page RPG).