If it's the end of OCW, then it's pretty reminiscent of their ROTS fight, if it's him as of the hypori fight, then Kenobi should solidly take him.
THE
TheNuisanceBirdWrecker - Scientist Class
ROTS Kenobi. I think that unlike their final fight it'd come down to way of the blade. Kenobi would be pressed but I think he'd eventually find an opening and exploit it. I'd be an intense fight though.
EMP
EmperordmbLSDMB
I personally don't really see the need to differentiate between OCW Grievous and his other portrayals in a verses scenario.