Black most popular. Yellow is second. Chocolate dogs need love too. Light colored yellows stand out when you are hunting. Chocolates blend best. Blacks are next.
Chocolates have a rap of being inconsistent where training to high levels is expected but there are some very good chocolate bloodlines.
All of that being said I have owned all three and run tests with all three and titled them in HRC. The chocolate was the toughest to train but the best hunting dog I ever had. I now have a chocolate female off of a GRHCH and HRCH that has all of the best bloodlines you could hope for from the chocolate kingdom of years past. I don't trial anymore but this dog is a good one!
Geezer should add to this thread...He has seen way more of them than me.