In the 35 years I've been playing the guitar, I have owned and played some of the all time classic vintage tube amps (they used to be affordable). Trust me I know the difference between tube amps and solid state amps.
There are some very good solid state/digital amps these days that I have no problems with at all.
JMHO/YMMV
Though my preference is tube amps, as I stated earlier, I will say that processing power and digital signal processing capability have progressed by leaps and bounds beyond where they were just a few years ago.
Understand, this goes well beyond the simple question of ”tubes versus transistors.” It is more involved than that. The real issue is one of processing versus tubes. Yes, I believe processing technology and processing power are at a point where it is conceptually possible to create a sound that is indistinguishable from a tube amp, to include all the dynamics, sensitivity, and harmonics that are characteristic of them.
To me, the real question is not, “Can it be done?” The real question is, “Has it been done, yet?” Or, “When will it be done?” In short, the real issue comes down to execution, not possibility.
Some would argue, with some merit, that it already is being done with Kemper. Others would disagree.
So, why do I continue to prefer tube amps? It goes along the lines of what
@ivan H suggested earlier. The easiest way to get a tube amp sound is to get a tube amp! Nevertheless, I can see a certain pragmatic value in using processing to get the same sound.