OK this thread is being sparked by a discussion myself and DBFan187 have had ongoingly. The question is clear.
I personally believe that the difference is easily detected by human ears.
OK, a watt is a watt. Amps don't color/warm sound. If yours does, then something is wrong with it EQ's and other processors do, but amps alone don't. An amplifers job is to amplify the signal it recieves. That's it. Nothing else. There is no audible difference between kind of amps.
Again, my personal opinion, based on years of experience in car audio... there is an audible difference in various amplifiers. I have based this on a comparison between a vacuum tube amplifier and a MOSFET amplifier. They both amplify a signal,true, however, even when both are set at default settings, stripped of all processing and equalization, I can still tell which is which. I can tell the difference, how about you?