Actually there is a huge difference between Braunvieh and Brown Swiss. Though both breeds originated from the same herds in Switzerland, the American Brown Swiss have been selected for the past 100+ years for milk production whereas the Bruanvieh have been bred as more of a beef animal (though they were considered a dual purpose breed in Switzerland).
A couple years ago in the Braunvieh magazine there was a picture of a Braunvieh and Brown Swiss heifer, of similar age, standing side by side. There was very distinct differences between the two heifers (i.e. thickness of the top and in the rear, etc.).
Because I live in northern Indiana I am not very familiar with the individual advantages of the southern breeds (i.e. Brangus, Beefmaster, Simbrah, etc).
If you do decide to go with the Brown Swiss cows I think Limousin or Charolais bulls would be a good choice to use. These breeds will contribute greatly to muscling and the daughters of these bulls will be more moderate in milk than the Brown Swiss.