I use a Weber mini mass. I've tried it with a variety of amps and been pretty happy with it. I only use it to practice at home though. I've never really used it to get power amp distortion with a Boogie. I have cranked a 15w Peavey tube amp with it and it got a very average amp to really sing.
If you plan to an attenuator with the volume up make sure the attenuator's rating far exceeds the boogie's power rating. Remember the power rating for your Boogie is measured at the point of clipping and the power the attenuator will have to absorb will be well beyond that.