Yes they get some very mixed reviews, and some very mixed publicity.
I haven't played through one, but from some bands I've heard that use them, they sounded pretty good to me.
Shadows Fall uses them, I believe the Revolution heads. I saw them about a year ago in a very small venue (200 people) and the guitar was very easy to hear.
Not to diss anyone, but the stuff you saw onstage was mostlikely empty...they've got racks of pres and otherstuff behind the backline that is decidedly NOT Kranktastic. They've got empty headshells onstage for effect and I guess they do use the cabs...but the tones...eh...not krank. I got an advance of the new album @ my job btw, the tones are pretty nice for heavy stuff.