Im gonna have to agree with DreamRyche2112. I own almost all of satriani's records and can listen to them the whole way through, back to back, without feeling bored, having my head want to explode, etc... On a recent car trip to NYC, i tried listening to a steve vai cd and couldn't last the whole way through. For me, the main difference is that Satriani seems to have a much better sense of whats going on melodically and harmonically in a piece- thats why its so easy to listen to. Whereas Vai demonstrates some of this ability, he seems to mainly shoe his virtuosity. It also appears that Satriani uses a great deal more structure and variety in his music, having recurring themes, and other compositional techniques that seem a little lacking in vai's music. Then again- im just a high school senior, so what do i know.