We had a discussion about this before, but I believe 412 are more of a novelty than anything, even for high gain and metal. The thing is they are hard to push to levels where you really feel the air on your back (that being honest, its the main mojo from playin a 412), that having one its only justified in very big venues, and even then, most likely you will mic your cab or go front house (which is the kemper main advantage for live IMHO). Looks cool tough.
Agreed!! 2x 12 is the more practical choice.