I've had an MK50 head and a Cornford 2x12 (Vintage 30s) since 2001 and it's been used for gigs ranging from local pubs to function rooms to big stages at biker rallies and playing off the back of a truck in an open field (without mic'ing up!) to a a thousand people at a firework display and I have to say it's brilliant.
I wrote a review on HarmonyCentral -
http://www.harmony-central.com/Guitar/Data/Cornford/MK_50_H-01.html- not long after I got and and I still stand by everything in that 5 years on. Since then I've got a Heritage 535 and put BKP Mules in my Les Paul and they both really sing through it - particularly when pushed in the overdrive.
It's often noted as quite a 'brown' sound (which you either like or not) but it really seems to bring out the identifiable characteristic sounds of instruments and it seems to encourage the sustain. The clean channel's great for twang from my Asat and a bit more crunch from Strats and humbuckers, and the overdrive does everything from Stevie Ray upwards whatever you're playing. It's also very responsive to dynamic attack when you dig in on the strings.
Certainly it's not cheap, but they do crop up on ebay at pretty sensible money and they are built like tanks with top quality components. There's now a Mk2 version that just got a rave review in Guitarist and that has an extra clean channel and some more complex loop switching which I'm interested to try.
Anyway I think they're tops, so there.
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