Not a breeder YET, but I do have experience from raising a kit to adult, almost.
Dobby and Kreacher are 10 months old today. I've had both of them from when they were 7-1/2 weeks. I met them for the first time at 5 weeks.
They are very friendly, well adjusted bunnies. I did make a ****oo with Dobby at 7 weeks by handling him wrong due to non-experience, but I did get that trust back and he is such a pleasure to be around.
The reason why we wanted rabbits so young is that we liked to enjoy the complete phase of an animal. Just like with our dogs and hamsters. It's just us.
I found that environment really does have a lot to do with good temperment. You might have a skittish or nervous bunny but can, with the right TLC, turn that bunny into a sweet creature who craves your attention. I do agree with Rue that a really nasty rabbit will come around that no TLC will do. It is best to not breed that sort of rabbit.
We decided that we would start our rabbitry with youngin's. Neville is 7 weeks today. Our doe will be as young as Neville, if the breeder feels she's ready, to come home to us. We want to raise them, thanks to the lessons and love from our other two, and then breed. We want to give them a good, balanced environment and then see what the kits are like. We will be hands on with these kits and see how the good, balanced environment will reflect in their sweet temperment.
Willard, our rescue, as well as Jake our "know for a fact" abused dog, could have been bitter and angry, but we were successful to show they were safe and loved.
99% it's we humans that make these pets mean and aggressive. I don't count does who are very protective mothers as aggressive.
We think very highly of our animals. Know they are animals but they are so much part of the family. You take your time, have patience, go at your bunny's speed, and truly observe and learn their signs, I think anyone would be success raising a bunny.
It's the breeder's responsibility to start their kits out on a sound road with a good environment, than it's the owner to continue it.
Just my opinion.
K