There is about the same difference, other then color, as there is between 2 line bred families of any other breeds.
The black folks have agreat marketing program (CAB) and it's done wonders for turning everything black.
We prefer REDS. It's a smaller gene pool, but most of the long time breeders have selected since the beginning for profit traits and didn't go for the giant animals that a lot of breeds did. Granted, there are some pretty big Red Angus, but they're not nearly as common as the huge Herefords, Shorthorns, blk Angus, etc.
In Canada they're in the same herd book/registry, in the US they're two seperate entitys.
dun