Well, having played low wattage amps from both Matamp and Cornford, I would deffinitely say I prefered the Matamp. That's not to say there's anything wrong with cornford, they do some good stuff, but I just find the Matamp does what I want better. I can't speak for the bigger models however, but I'd imagine it'd be much the same story.
I think considering the price of even some mass produced amps, like Fender and Marshall etc, that Matamp offer exceptional value for money. You get what you pay for and then some, and you can't really put a price on the kind of customer service you recieve, they're top blokes.