I've been fascinated with the idea lately, I was originally thinking of amps like the Hughes and Kettner Metal Master (it does have a solid-state power amp) or the Marshall JCM-1H, but I kind of like the EHX English Muff'n in the demos.
Probably won't get anything and don't really need it, but I thought it make conversation 'cause it's really hot and it's somewhat boring here.
I've got a tube OD pedal that I love to bits and it really does sound more pleasant than 90% of other dist/OD pedals I've used, even with solidstate amps.
It's definitely not the same as using a full tube amp. but if you dig the sound, why not? I'd definitely try one before making any decisions.
I think that to be a heavier distortion usually two valves are needed, so that one has some kind of solid-state gain stage. Actually it's pretty obvious if you get the schematic.