If all you are looking for is pest eating pets then get whatever you want. If you want friendly ducks, get day olds, keep them inside for a few weeks and mess with them and interact with them as much as possible everyday. Talk to them, offer them yummy treats out of your hand etc...this will entice them to see you as the provider, not be afraid of you, your hands, or movements and will go along way into keeping them tame as adults if you keep it up when they move outside, going out 2-3 times a day and offering them treats by hand and rubbing them.
As a kid I had Pekins, Mallards, and Muscovies...
Now I have 1 mama muscovy and her eight babies, 5 magpie, 2 buff orphington ducks, and 3 runners. My favorite and most friendly are the runners who I've had only 3 days because they were raised in a classroom and were extremely well socialized. My 2 buff orphington are good ducks too, very pretty and i've heard pretty decent layers.
Muscovies in all honesty are big ducks, but seem to have some of the best personalities and are just all around great ducks. Great foragers, big and goofy, good layers, go broody well, can easily be tamed and be friendly if handled as babies and positively reinforced, and make excellent excellent mothers. Also muscovies tend to be very quiet, as they dont honk and quack loud like other breeds of duck, they more do a raspy hiss both males and females.
If you are not looking to breed and just want a colorful diverse flock, get that. Get you a mix variety of ducklings to raise together, definately get more than you are planning to keep to account for drakes as you are not going to want many drakes, 1 drake to 3 females is about the least # ratio I'd suggest. So if you are looking for 3-4 ducks to keep, get 6-8 so you can maintain a healthy ratio so the male(s) dont tear up your females and when they get old enough to sex, then rehome the unwanted drakes.
good luck and enjoy the ducks when you get them
