!!!!!!!!!!!!!!!!!!! Beat me to it!!!!!!!!!!!!!I get the same reaction when I run SansAmp into the front end of my GK 700RB into my 6X10 Ampeg. I think a big part of it is the large, recognizable, branded cabinet that people have seen since the 70's. Part of it is how much more clean and loud you can make the bass with a rig like that.
Played an SVT with two 8x10's for about a decade in the 70's to very early 80's.
Never heard or felt anything close to that until we did a charity gig and the other band's bassist let me use his rig(SansAmp Pedal>GK700RB>beat to heck SVT 8x10). Only had to tweak things a tiny bit to make THAT rig sound extremely close to an SVT head-pushed SVT 8x10, same tear-drop sound field in front of it, same "touch your strings and they play themselves" feel, same crisp bite and punch at the same time. Came real close to getting a used 8x10 and SVT Classic after that but children's college expenses got in the way.
@Crazy Pines : When they are maintained and working properly, the SVT(tubes) + SVT 8x10 cab is amazing and sounds/feels like nothing else.