I have the Mk 50 II and it can pretty much cover all ground. It's basically like a 3 channel head though they call it a 2 channel....Clean(Fenderish), Dirty(Good plexi), and Boosted dirty(Soldano..without the mid honk). They arent a real compressed sounding amp...its very open even at high gain settings...which makes it pretty unforgiving....but totallhy dynamic.
Even at full saturation rolling the guitar volume back will give you a very desirable clean....similar to that of a Marshall plexi.
It has dual master volumes, separate channel volumes for easier level matching, and assignable dual effects loops..so if you chose to run effects only on your clean channel, you can assign it so when you switch to the clean, loop 1 is engaged and when you switch to dirty the signal is unaltered as it changes over to loop 2...or you can run another proecessor in loop two which will engage when dirty is selected. The loops are the best Ive heard a far as not mucking the tone of the amp up completley.
The older style Mk 50(black one) single channel is a little rattier sounding in my opinion, the Mk II is a little more refined....smoother. Neither amp is very common in the states so finding the MK's used is pretty rare and you'll probably pay close to retail depending on condition of the amp.
The website has been down for about a week. Dont know why...the forum is down as well. My guess is they'll launch the new site after NAMM.
If you want to buy new, contact Wally at Solidbodyguitar.com. He's in Minnesota and is the main US Cornford Rep.
L8r