Eric Pritchard has studied this. He has some opinions on the way they sound. It may not be the ground truth but he has tried to emulate the tubes sound in overload with SS. He builds guitar and microphone amps.
In the music industry the main issue with SS is how they overload badly - try telling a musician and a band that yesterdays sessions are all useless becuase some SS mikes were overloading (not great for repeat business!!). I don't agree with everything he says but I share his believe that overload behaviour is the major difference. (Most people do not realize how easy it is to drive even a very powerful amp into overload without necessrily souding loud...speaker that are difficult loads are often to blame)
In the music industry the main issue with SS is how they overload badly - try telling a musician and a band that yesterdays sessions are all useless becuase some SS mikes were overloading (not great for repeat business!!). I don't agree with everything he says but I share his believe that overload behaviour is the major difference. (Most people do not realize how easy it is to drive even a very powerful amp into overload without necessrily souding loud...speaker that are difficult loads are often to blame)