I get the impression that many listeners thinks tubes are great because they love the nice relaxed sound they deliver in some systems.
But the reality is acoustic instruments whether string or brass contain alot of noise in their sonic profile. The pretty sound tube systems provide exists only in tubeland.
I recently recorded a concert band and as usual was struck by how harsh much of the sound coming off the stage was in comparison to recorded sound most people experience every day at home. In fact recording engineers spend alot of energy removing midrange via eq and by using ribbon mics for example to smooth out the sound. Tube gear sounds good because it sounds good, not because it is accurate. The opposite is the case with solid state. It can sound harsh because the real source music is often quite harsh and aggressive sounding.