From personal experience, I can tell you that hairy calves don't do terribly well at the market. Also, Highlanders tend to mature slower than some other breeds. If you are keeping his calves to finish and slaughter, I might go with the Highland bull as the beef is truly excellent, otherwise I would go with the black if you are selling calves to market. I would be careful as well about damage being caused to the black bull. When I had my Highland bull, he got into another bulls' pen and pretty much ripped his sheath right off throwing him over the fence.