It is easy to forget that volume, as we perceive it, is a log 20 scale. In other words, to double the volume from a 10 watt amp, through the same speaker, you need 100 watts - 10 times the power, not just double the power. Doubling the surface area of the speaker(s), from 10" to 12" or 1 12" to 2, or 4 or 8 also gives a similar increase - almost like doubling the volume, though beyond 4 speakers, the phase cancellations begin to reduce the effect.
Further, watts are watts, no matter what makes them. That said, tube amps reach their rated wattage at the distortion level listed in the specs. They can make more wattage, usually, if you are willing to tolerate more distortion (and I bet you are). Solid state amps reach their rated wattage and stop. There is no more on tap period. That contributes to this idea that tube amps are louder, at the same wattage. Really, they are making more wattage, esp. during pick attack where SS amps just clip.
Now, tech aside, I strongly prefer a tube amp because of the dynamics. SS amps have a very linear dynamic response. Tube amps jump when you hit a string, causing the player to use more nuance. You almost do not need a volume control. You can control how you sit in the mix, just by picking style. Plus, the clean tones are much better. Even simple 'cowboy' chords sound good. And distortion, forget about it. A $100 pedal will never even get close to $2000 amp with the preamp tubes, power tubes, output transformer and speaker all contributing little complexities to the tone.