6V6's, Usually 15-20 watts per pair, more early breakup.
EL84's Usually 20-30 watts per pair, same early breakup as 6V6's, but more high end, less crunchy, more sparkly
6L6's Usually 30-50 watts per pair, more clean headroom, great crunch when pushed.
EL34's Usually 40-60 watts per pair, maybe less headroom than a 6L6, more crunch and distortion when pushed.
This is very rough approximation based on my experience only.
My favorite tone is a 6L6 cranked, but its usually too loud to be practical. I used to have a 70's twin reverb, and every now and then I would dime it, and stand in a different room, and the sound was glorious. It also had the JBL speakers which helped.
The best live sound I have ever had was a blackface Bassman cranked to about 7-8 and it also sounded amazing, but also ridiculously loud.
I actually like solid state amps as I find they sound just as good as tube amps at useable volumes, and have a more consistent tone over the range of volume.
The only time I think a tube amp sounds better is cranked, loud.
There's nothing like it!
Power output usually has a lot more to do with the transformers than the tubes, but what I suggested seems to be the norm for theses tubes.
Cheers