We have only done kune kunes, by far the friendliest breed, and although finish later than most of the traditional breeds, they tend to need MUCH less feeding, even better to feed mainly on grass and vegetables (not from the kitchen though!).
We tend to find castrated males the easiest to deal with as they don't get hormonal.
Our last were sent at about 14 months as it suited us time wise, and at 60kg deadweight, comparable to 'big pigs' And they taste really good!