What is meant exactly by the description 'more musical'?

@atmasphere Like many here i've followed this discussion with interest, especially as relates to the discussion re sound or "musicality" of tube amps v ss--and i will say that in general i agree with you--just never knew the reason why--but as an expert amp designer what is your take on hybrid amps that use both tubes and ss at the output stage--do these amps suffer from the same issue as ss amps?  or are they better at dealing with the higher-order harmonics b/c of the tubes?  i.e. is having a ss output stage going to inherently have the unmasked higher order harmonics?

@atmasphere You're right--a bit over my head on the technical side but i appreciate the effort.  What about hybrid amps that don't use feedback--claiming to use zero feedback to "maintain harmonic integrity"--eg Aesthetix--still a problem?  I'm not asking you to comment on that product line--just the design.  Having owned both tube and ss amps i am looking at hybrids as a solution to the problems you outline above--basically a more "musical" amp to drive low efficiency speakers.