To be honest, after seeing VGLive, I wouldn't buy the CD. The arrangements for the most part aren't anything you're not going to find anywhere else. The primary draw of the show is the fact that you're seeing it, well, live. Other than that, the track selection is fairly standard/straightforward. Mario, Zelda, Halo, WoW; all relatively "mainstream" titles as far as game music goes.
Also, the Mario and Zelda arrangements are the same ones we've been hearing over and over again since Orchestral Game Concert. A lot of the other music is straight stuff from the games with very little arrangement at all, considering they're from more modern games.
A CD like this is for a person who still finds game music played by orchestras to be a novelty; the audience is there, but for people who listen to OC ReMixes, OSTs and arrange albums, I don't think that you're going to find this CD to be particularly impressive.