I used to use valve amps back in the days when there wasn't a choice. Heavy. Unreliable (and I knew how to keep it fettled!). Sounded fabulous.
I always wanted a silver face 50w Bassman and 2x15, but couldn't lift the cab.
Now I have the Barefaced Super 15, which sounds like a 2x15 should, and a Little Mark III. Good as valves sound, this is also very good.
I would say that there's not too much difference. Certainly some, but not much.