A 10watt tube is probably as loud or louder than a 40watt solid state.

For a relation example; my 40watt tube at 3 is louder than my friends 30watt solid state at 9. He uses a boost pedal to get the volume up there.

A small tube amp cranked would be distorted, but that is good. Generally clipping a tube amp is very useful and the sound is great, I think.

If it is a good quality small tube amp, then ya the sound will be great. I played on a 10watt Fender Blues Junior and thought it was one of the best sounding amps I've ever played on.