Obviously, comparing a $500 monoblock with a $3000 stereo amp (say Rotel vs Parasound). The Parasound is going to win. I took this question to ask about amp topology. Not which amp actually sounded better.
Say you have a monoblock amp and a stereo amp with all the same component quality, driver circuit design, output devices, power supply capacitors, etc. If the stereo amp uses a shared power supply, then the monoblock is going to sound better. It may still sound better even if the monoblock is single ended. If the monoblock is fully balanced/differentially, it will beat the stereo amp (as long as the it is properly designed for balanced topology -- some amp circuits do not bridge/mono well).
