OK,Let's think step by step,
What is the reference system? It is the advanced system, right ?
so OP want to ask
Which is the advanced system,Tube or SS, right ?
However, a lot of people use tube system, while a lot of people use SS system. When you listen more and more, you can simply figure out it is not advanced or not, not high or low.
The sound come from tube is different from the sound coming from SS.
When you think one of them gotten be more advanced than the other,there is endless argue about it. When you think they just different, choose what you like , there is not argue.
and will have peace of mind and just turn yourself in the music.