I just got back from seeing the Reverend Horton Heat in Sydney.
Jimbo Wallace was using two RB400s with two 4x10 and two 1x15"
I suspect, though, that he was getting most of his tone shaping done by the little red box on the top of the two stacks. It looked to me like Raven Labs master blender.
I have to say, I wasnt thrilled with his sound. It was classic scooped rockabillly bass, though with lots of thundering lows, and clickety tops, but not alot of what I would have called note definition.
I had a whirl on a MB210 in the shops with my upright and K&K pickups and pre and was damn impressed!
And they are so light.
Ive been using a Nemesis 210 now for about 10 years for smaller shows, and been really happy with it, but if it did come time for a new amp, I would certainly be trying to get the MB series to be beaten $ for tone and weight for weight against all comers.