Just got this the other day. The 5.1 mix is really good! The opening 2112 Overture sounds big, spacious and punchy with loads of depth and detail. Alex's buzzing amp is clearly audible in the back of the sound stage (for better or for worse) and every guitar and bass lick is clearly rendered. And the drum sounds... let's just say that air drummers will get a serious workout listening to this. What a blast!
This is the best sounding Rush DVD-A I've heard, clearly better than Moving Pictures or Signals. The Signals 5.1 mix is pretty good, but the overall sound quality of that album is crippled from being recorded in stone-age 14 bit digital.
Russ