well obviously the song is good, I'd even say great but this has nothing to do with Steve Vai man...
Since everything positive have already been said about this song, I'll say what I think could have used some improvement.
First of all, the drum sounds are not very good; it looks like the guy went for a true drum feel but didn't succeed very well. Maybe that's just my impression.
Second: the samples from the rhythm track aren't up to par either, but well that's a pretty old mix. I still love those "icy" glockenspiel things going on.
Third: I don't really like the guitar tone... too loud, too compressed and too chorused, but that's all too subjective.
Four: Nothing overly original about this song except he did away with the triplet march style and went for a 16th feel in place. Of course there's always the solo and the break after.
At 2:40, I don't really like what's going on with the guitar (beginning of the solo). In fact I don't like the first twenty seconds of it, but the rest is purely great. The slow break after the solo totally HAD to be there, there's no way around it so props for that.
Now I'm just reacting to people saying it's the best music ever. When I say I don't like something in this remix, it doesn't mean I think it's crap, it means I think it could have been better and therefore this is not a perfect, amazing, the best ever mix.
In terms of guitar playing, I can clearly see a distinction between Ailsean and known pros like Steve Vai or Joe Satriani or Mark Knopfler, whereas I think McVaffe's Drum'n Bass grooves or Blind's trance are up to par with the pro ones.
So to sum up, I have to say in all humility as a guitar player that I do not think I could have done something as good as Ailsean's work (cause we have to admit, he's got talent) with this ReMix, but I still don't think it's perfect.