I've been using a WB100 for about a year now. Into a Barefaced Super 12. It sounds pretty, pretty good...
A couple of months ago I got a Vong Filterung (HP+LP filter with a level boost) and have been using that through the effects loop.
I have to say, this has really opened the amp up. Before now, I've always been just on the edge of distortion and having to play hard to keep up with my (loud) band. Especially with low notes. I do play a p bass with heavy flats and the tone completely rolled off, so it does take some oompf to get the pitch audible, especially playing with 2 guitarists who are playing with lots of mids in their sounds.
Feels like the amp I always wanted now. Much more dynamically responsive. Very loud, but not aggressive when I want it to be, solid and musical when I play soft and consistent up and down the neck.