The GK lurking in the back smells bass player indeed ;-)
Not every amp can handle the extreme range of a Hammond organ with pedals. The GK rocks.
It's also my main gigging bass amp. The only other bass amp I use now is a little battery-powered Roland I use to add depth to my acoustic Microbass.
In my club gigging days I used Ampeg B-15s.
I never had an Ampeg, but I do have a Roland Micro Cube Bass RX and a GK MBS III. No big box at the moment, though I'd like to get something that projects a bit more for my project studio/rehearsal room.