i'll throw in my $0.02 here.... we just had rooster harvest day with our mixed breeds... some were about 6 months old and they were tender and delicious. and to be fair we used most of the carcasses for roo stew as they werent huge... but the breasts were perfect pan fried.
i think the ratio is supposed to be one rooster per 8 or 10 hens...
as far as qualities - it depends. we kept my arch nemisis - Fred for his ability to watch and keep the hens safe. he calls to them when he finds food, the 'flock' to him and stick close by, and he protects 'his' hens from the other roosters. but Fred has a bad attitude toward me and i keep my shepherds hook in hand and never turn my back on him.
we also kept Big Pansy, our newest roo and an enormous wyandott mix. he has a gentle nature but the hens dont naturally follow him. we're hoping this will change as he matures.
Fred is a better hen keeper, but BP is bigger and we're hoping for larger chicks - Fred's are a bit small. we got rid of the roosters who led the hens out toward the road, down in the trees, who attacked my husband and the three little ones who were just a menace. they ate all the food, ran the hens around, and ran from me when it was time to go in.
hope that helps!