I was running it into a Barefaced Big Twin 2, mostly using my pair of Maruszczyk Frog 6-strings. I’ve been using an Ashdown RM-800 as my primary head for some time, so that was my benchmark in terms of tone, volume, etc. Agedhorse made some suggestions earlier in this thread about how to use the EQ (which works additively, effectively as volume controls for certain frequencies), but, even with that, I couldn’t get the gain up past about 10 o’clock without the whole thing fuzzing up. I like some hair on my tone, but I also like to be able to not have it. And using the EQ controls in the manner they were intended to be used did make things louder, but not sufficiently so for me.
I owned a Bass 400+ back in the day too, and I don’t recall ever having issues with getting a clean tone with that, with it only getting furry when you hit it hard, and in a pleasant, “creamy” sort of way. If you cranked the input gain it would fuzz out, but only towards the extreme end of the gain knob.
I’m not giving up on Mesa though. Probably going to revisit the WD-800 at some point - I had one for a while and liked it a lot, but couldn’t justify holding onto two heads at the time.