My (worthless) thoughts:
They should have had a baseline for what riffs were played. I think some of the amps suffered simply because the players were screwing around with single-note crap instead of really trying to showcasing the amp overall.
Blackstar: Not bad overall, but I wouldn't buy it.
Diamond Nitrox: Was more impressed with the clean channel, which doesn't mean much in a high-gain shootout.
Diezel VH4: Contender for best of the lot. Don't know why they added the TS--didn't need it.
ENGL Powerball II: Wasn't impressed, actually disappointed.
Framus Cobra: Good tones, on the fence about this one.
Fryette: Impressive, a little dark for my tastes.
H & K
Coreblade: I don't think the demo did it justice. Sounded like they had it turned down & I think they should have left the effects off. Great-sounding amp, although a bit overpriced IMHO.
Krank: Krap
Mesa: See "Krank"
Orange: Too much fuzz in the distortion. If they cleaned that up, this could be a contender. Great clean channel.
Peavey: Good all-around amp. Definitely in the top of the class.
Randall: See "Krank"
Soldano: Don't know why they didn't showcase the SLO100, but great tones, definitely in the top of the class.
Overall, the Dimarzio pickups sounded better across the board than the SD pickups.
Top 5: Diezel, H & K, Framus, Soldano, Peavey
YMMV
Cheers,