The big gimmick with this (besides the LED knobs, and yes, the tone knob doesn't light up, kind of annoying) is their Alternative Internal Resonance technology (AKA A.I.R.)
It also has three "sound tubes" going from the bridge to the other end of the body that transmit vibrations to all the layers of the wood.
Here's the Yamaha page for it, there's a little flash animation that shows a cross-section type deal for it.
And it definitely does resonate well; it's incredibly loud even when unplugged, far more than most basses I've played (never played a really high-end one though), but one thing that gives me pause is on low notes (especially an open low-e) it has this sorta strange harmonic overtone quality to it that almost makes it sound like it has a chorus on it.