Now this is a comparison that doesn't get done much. We have all of these amps in our sound room. I spent the evening yesterday doing some comparisons. A quick review..... A single MC2000 is still the best sounding tube amp that I have ever heard! The bass is very smooth and robust, mids and highs are smooth without losing any detail. The MC275's in mono were actually quite good. And up to about 30 watts, kept up to the MC2000 very well, but when a good low frequency song would kick in, it would become very muddy and loose the clarity.