I was in Madison last night and was fortunate to see the Cavies, Cadets, Glassmen, Scouts, Blue Stars, and some others.
As far as pure volume goes, the Glassmen or the Scouts were the loudest. The Scouts opener was pure "pedal to the metal" intensity for almost the first 25 seconds.
One thing that I noticed about the Cavaliers was that their synth sometimes covered up the band. At the end of a large crescendo, it seemed that even though the corps was getting louder that the synth might have covered up climax of the corps.
So, for pure volume, as of last night, and with the limited number of corps I saw, I would have to say that the Glassmen are the loudest this year.