If you are going to AI them then get what you like and have 6 different breeds if you want. You will be able to see what does best in your area, on your farm, and then go from there. Yes, if you sell calves then you will be looking at the "saleability" of them and what does best in your area. Where are you located? Maybe put it in your profile so if you have a question or problem, people from your area can better advise.
Unfortunately, "black" seems to be what sells in most areas, and if you have 4 females, you will hopefully have 4 calves, then next thing you know you will have "more" and then what ???? Good problem to have, but you will not be able to "eat the bull calves" if you get 3 every year and then what do you do with the heifers? So that is the reason for some to advise about the breeding black to have saleable calves. Like Walnut Crest said, you don't want to go broke in the process.
But since you like the looks of the hereford, get one and see. If you breed AI and they are all purebred stock, registered?, them you could sell a few calves down the road as registered or for 4-H or FFA or something. We like our few herefords in the mixed commercial herd we have and since they are discounted we always breed them to an angus to get BWF calves that will sell well.