The first thing to make note of is that there are two versions of the system: The so-called Victory Point System, which is driven by attribute+skill using dice pools, and the d20 OGL version. The d20 OGL version has not been updated since it's release to my knowledge.
So the question becomes complicated by your stated use.
If you are familiar with d20 OGL, then that version would be recommended to a beginner to the background.
However, if you are not, then the latest version would be my recommendation. The VPS has remained the same among the three versions- the difference is a change in evolution, i.e. with each version, the rules have been tightened, and the fat sloughed away to create a more digestible system in its current iteration. The content of the game is also the latest in the 2012 version- there aren't too many differences, but they are there.