I would say this would be a good comparison IF the DM12 weren't so insanely overpriced.
Demon wins efficiency
I believe the Demon wins weight, but they're close
Ergonomics are highly personal, I like the Demon better because of the trigger
Demon has multiple bores, so wins the barrel
CS is a draw, I've gotten great CS from both companies myself
Packaging the Demon wins, although a larger package, I just like it more
Looks is yes, preference, here I actually prefer the DM12
Maintenance is a draw
Kick is a draw
Feedneck is a draw
Reliability I give to the Demon, because the eyepipes still are a shi**y idea and break too often.
Sound I've never heard them back to back so can't say.
Consistency is a draw
Demon wins for accessories since it includes a rechargeable battery and is internally plumbed.
Demon CRUSHES the DM12 for the board since it includes a full color OLED not LED (this is the big one for me, I'm color blind so programming LED boards is horribly difficult)
Demon is also like $200 cheaper.
IMO, it's a no brainer. The DM line honestly hasn't improved since the DM8 other than a few ounces, and actually regressed in some aspects (eye pipes) while their competitors have made leaps and bounds of progress.