I'd look for what's popular in your area, unless you just want to introduce a new kind of beef. Down here we tend to have Angus and Brangus. Angus can be fairly docile if you raise them from a baby, Brangus have too much of the Brahma (Bray-mer is how they say it here) disposition and can be ugly. Oh, there are several Charolais (shar-LEER down here) folks around but those guys get HUGE. Lots of yield but I wouldn't want to be a beginner and have to wrangle those things, sheer bulk will get you killed.
The mini-cattle don't get much bigger than a medium sized horse, 800-900 lbs, and they are supposed to have more usable meat than the full sized steers. They aren't real popular here, so don't have first hand knowlege.
Good luck and be careful, cows are not at all like horses to handle.