brianv4
Fractal Fanatic
He uses KW series that are dedicated for his guitar. problem with using "vocal" monitors (as part of a sound system) for your axe/guitar rig is that they are EQ'd for the intended purpose, not a flat response at all.
yet dweezil is using k12's which buy most people's accounts are "vocal monitors". I've went with no amp at all once and played through the vocal monitor and got by fine... not preferred, but i'm not that much of a diva.
Some sound guys just fear change, and only want to do what they know. Once in a while you will meet someone who is open to new things and not immediately shut you down... it's rare though.