When I was looking into getting a CTM 15, I seem to remember reading something from Ashdown along the lines of "15 watts of all valve power", which, technically, is correct, as the phase splitter and power stage IS all valve!
I've used it for recording bass and guitar, and like the sound it makes, but, since they are using a solid state front end, I'd have preferred a proper 3 band +/- 15dB eq over the old fashioned valve-style interactive eq.
And like Bigwan here, am not sure about the tone change as you wind the gain up.
I've also gigged it twice using 2 12" cabs and I liked it!