Just had practice with this bad boy:
Cranked, this head sounds fantastic! Zero clipping and had ridiculously versatile controls: the EQ seemed a lot more responsive than the GK and Hartke heads I'm used to playing. The tube preamp is great, and I'm primarily playing using about 75% blend from the tube preamp. Fan isn't loud, responsive controls and a volume that seems to be a lot more powerful than 200watts RMS! British amps must be conservative.
This head overall has tone that reminds me of a Trace Elliot, but without a little bit of the color/"funky" treble that defines Trace Elliot to me. Not sure if that's a great explanation but Trace always seemed to have that distinctive punch to it. This Marshall head is a lot more versatile to my ears.
I played through a 80's 4-ohm Peavey 2x12 cabinet loaded with EV-12's and the sound had great clarity and enough volume to be easily heard with my band (one guitarist and one drummer). Only time will tell if that translates to gig-able volume but I think it'll pass that test too. Very happy with this head and the fact that it's a bit unusual is pretty cool to me!