I have had no luck with latex paint lasting on hand rails. I took mine down and spray painted them. They are holding up well. A oil base paint might hold up, but I never tried it. I still think spray painting gave them a smoother finish.

Mine are the same color as the wall. It's a modern look. They have held up fine. I was originally doing it as a temporary measure but they look good.

you would need to "prep" the handrail thoroughly, if you decide to paint.

(remove and sand with 220 the entire handrail to scuff the existing varnish and give the surface some 'tooth'. A degreaser would also be advisable to remove existing grease from hands, such as "liquid TSP". Prime with a good oil or latex primer like Kilz, Coverstain, or Bullseye123, and then paint...)