Both breeds are a nice choice when it comes to a family breed or for kids. I myself am a devoted Cochin fan, and the frizzles add a nice little kick too, lol. It really comes down to a personal preference. Brahmas only come in a few varieties where as Cochins come in several. If I were to give advice though, and not just because im a Cochin freak, I would say Cochins are a more docile, easy going, and layed back breed. Brahmas arent terribly flighty or otherwise a pain, but there is just something about Cochins. The best advice I can give is this: Get a pair of so of each breed and keep them awhile. You could even get chicks, that way you know the tempermant as chicks as well as juveniles and adults. Then you can make the choice for one or both breeds, and which suits your families needs more.
~Casey