I think they would fair equally as well as all the other colors. If they're good, they're good.
The darker the color the more light is absorbed. The lighter the color light is reflected back to your eye more.
Black cattle with hair comparativeiy speaking who get lined up in a class with all other colored cattle appear to sometimes look better then lighter colored (as in Light to darker tones) because the holes they may have are more disguised. With hair and a nice sheen, black is hard to beat because light is being absorbed and at the same time,the sheen reflects some of the light back to your eye which is why they can look pretty dramatic and stunning when all groomed up.
Ironically, it's your mid-tone calves which general look better in a slick show. The judge becomes more programmed and really have to look when evaluating the cattle. Black can become lost and more difficult to see and the lighter toned cattle seem to show up better. Really dark and your lighter colored calves can sometimes come across as being coarser made because when the light is reflected back there is more contrast in light and dark. Middle- toned cattle appear to even the light out better and therefore look smoother, but like I said if there good. there good and probably should not make much of a difference.