Nothing yet. Since the front suspension has lots of travel and soft springs, a brake pad with too much initial bit could lock the wheel before it has a chance to load up.
I'm partial to Vesrah, and I think they make the RJL compound for the Ninja 650, so I'm going to try that. I'm cheap, so I'll wait until I go through these brake pads.
My Gixxer 1000 with Vesrah SRJL pads and a Brembo radial master cylinder has too much bite. I have to be very gentle or it will lock and put me on my a$$. Yes, you can have brakes that are too strong.
"ride more, worry less"
2005 Suzuki GSXR1000 (slightly bent) - Track
2000 Honda VFR800 - Street