We have had cattle running with my dad's for the last 12 years in a commercial herd. The bulls that we used consists of Brangus ,South Devon , Hereford, some Santa Gertrudis at one point. All contributed some great qualities. Th Santas gave us a few more calving problems , but some great big meaty offspring and really good mothers and marketable steers. The South Devon {some of my personal favorites} gave us some really nice frame size on our mothers. Their calves are always ones you hate to part with.The Brangus did some of the same for mothering and fast growing steers and nice replacements. It's hard to beat the Baldies for contant producers and good mothers. I think it takes a very careful acessment of your individual herd , year to year to make the right decisions. My dad has passed a couple of years ago and now it's up to us to make all the decisions and I see the things he looked at when he purchased a new bull . It is the market in your area , but it it soooo much where your herd is at , at the time. It takes different Breeds to make a good market product and it is not the same answer for everyone. You know your herd better than anyone.