Honestly, I prefer my S. Cochin. Even though she was a free ranger and I didn't get her til she was 5 months old, so she's not uber friendly...theres just something about the big fluffy chickens I love. Thats why I ordered the 4 new ones in Standards.
The bantam ones are really cute though. So I guess its just a choice of space and whether you like big chickens or small ones.
The little ones are tougher and feistier for sure. My white B Cochin is the head honcho. She used to put our roo in his place, which was hysterical. He would chase the other girls and the cochin would chatter at him til he hid his face in the pine tree, and he would stay there til she let him out lol. The ones from Kim definitely let the others know that they may be small but they aren't taking any crap! lol