I like the convenience and power of the BB. For quieter gigs, it's fine with the one 15; louder gigs need an extra cab for higher end sounds. I guess my only complaint would be the weight; it's over 100 lbs and can be a bear to lift by yourself.
I have an SWR Black Beauty combo with a 15-inch speaker. I just bought an SWR cab with 4x10 and a horn. On stage, what's the best way to stack them? Should the 4x10 or the 15 be on top to get the best sound?