I have 3 Pekins, by pure luck, I picked out 1 male and 2 females (yay!) They are wonderful pets, especially the drake, he follows me around the yard while I do my chores, and if I don't stop and pet him once in a while, he will peck at my leg to let me know he needs petting hehe. He is a good dog, er... duck I mean.
I let my chickens out in the yard with the ducks during the day, and separate them at night. the drake was a little aggressive at first, but quickly calmed down. once they reach laying age, you can feed them the same food as the hens (I use purina sunfresh crumbles) while they are growing, I fed them Purina Flock raiser.
Pros list:
They are fun to have
my pekins are very social
The eggs make Great cakes and brownies (I don't like making cookies with them though, chicken eggs do better there)
They will clean your yard of bugs in no time (but won't eat scraps of food like the chickens will)
now here is the cons list:
they poop a lot
They dirty up the pool very fast
they poop a lot
The eggs are hard to get rid of
They poop a lot
they dig holes in the yard after a good rain
they poop a lot
and finally, they poop a lot
Hope that helps you a little, ooh, did I mention that they poop a lot?