When I bought it I hadnt gotten a lot of riding in this winter. So when I first sat on it I didn't feel like the ergonomics were "that" different. Of course the peg forward and higher than the Busa. But the PO of mine put pro taper bars on it so I don't know what factory feel like. But after getting the chance to ride both back to back there is a huge feel difference between the two. First bike I've owned without a fixed front fairing, so going between the two with that is weird. And I discovered I like no windscreen better, I'm 6'2 and the windshield on the Busa shoved the wind right and my shoulders and lower helmet.
Compared to a gen I busa. The torque feels better, as does the responsiveness. The brakes feel, and are far better. The b king feels a lot heavier till your moving, and the handling is different. Clip on bars on the Busa feel rock solid turning, like they take more force to steer making them
feel more stable (to me) where the handling on the king feels like it takes a lot less input to change direction. The turning radius is also better on the b king.
**edit** oh yeah, and when riding the Busa now, it seems like it's 2 feet longer just because of the stretch and the fairing, weird.