Why would anyone want class AB amp when class A always sounds better ?


Cost ? Heat? Reliability?
inna
My buddy has Klipschorn corner speakers.  He runs them with CJ premier mono block tube amps.  So tonight I brought over an old class A stereo amp my partner put together with some old parts we had laying around. 1.5wpc 45 tube pure class A.  Needless to day the Class A walked all over the CJs.  It was not even close - better everything including more bass and deeper bass output from 1.5 watts.  Music just poured out of the system, tone and space was killer, wide open musical sound.  So dynamic and delicate at the same time.  I may have to get some horn speakers now!

Happy Listening. 
Orpheus10, I would say that tube phono stage is most important. SS class A line level preamp and class A power amp can be quite acceptable, at least.
Most people, if not all, do prefer class A amps and integrated amps from the same company, be it Accuphase or Luxman or Pass.
One has to take the time ( as little as absolutely necessary) to pause and reflect on the reality that written or spoken opinions are largely driven by the insatiable need to be acknowledged.