Well, since no one has commented on the Buffs, I'll throw my opinion out there. I have both breeds, and I haven't had them for long, however My Buff ducklings are more people friendly than my WH. I had read that the WH were more calm, and friendly, but I haven't found that to be true. I ordered five of each from metzers, and got one extra buff along with them. Some of my Welshies are more calm than others (the boys mostly) but the buffs are by far beating them out in how calmly they take everything.
My WH like to sit by me outside, or be within sight of me. but my two buff girls step into my hands like a chicken when I go to pick them up out of their brooder and take them outside. They would much rather be sitting on my lap, than on the ground, and love to be petted, and rubbed on the backs of their necks.
Both breeds are wonderful though, my WH are pretty sweet, and love all the ducks, when my wh boy wasn't doing very well my two wh girls would lay with him by the water bowl, and heard him over to the feed bowls. He's still a runt, and the others are growing BIG so they're extra careful with him.