I got turned on to Satch and Vai at roughly the same time a few years back. At first I can see where all the comparisons come from, but after listening to them for a while you can see how different they are from each other. I agree with what's already been said on this thread about how some of Vai's songs surpass Satriani's. I'd kill to be as good as either though :p As far as listening to an entire album through I gotta give it to Satch as well. He has a knack for making catchy guitar tunes, there's just no two ways about it. I think; however, that Vai pushes the limits more in terms of his songwriting though. Both were great when I saw them live. Additionally I own Vai's "Live in Astoria", and Satch's "Live in San Fransisco". Perhaps this is just because I got the Satch DVD more recently, but I think I prefer "Live in San Fransico". His songs are very personable, and I get a better glimpse into who he is as a person.