Had aYBA200, its fine, but not especially valve sounding, which is kind of a win for a well engineered amp, being not really coloured and distorted, but might be better served elsewhere. The are less expensive than Matamp because they are mass produced PCB amps, they are less expensive than Orange because they don't give loads away for exposure. I didn't take mine apart to assess build quality, but it did fall out of the bottom of a flight case and play the gig.