In the spirit of complete revelation, I must admit that I actually have a co-author's credit on one of the 2nd edition books. (Hearts Swords Flowers. It's good; you should pick it up. One day I might even get paid by the publisher for my work. [I'm not holding my breath.])

The reason that I suggest that you should pay more attention to first edition than second is that the latter really took the "generic RPG core mechanics book" a little too traditionally, so instead of being just a slim pamphlet of core mechanics and very focused ideas, it wanted to turn into Hero or GURPS – along with being a several hundred page nightmare which tried to provide individual mechanics for everything under the sun. That didn't turn out to be a really competitive product, in the end.

Which was sort of a shame. I was looking forward to writing more stuff for them.