If you are just getting ducks go with Metzer Farms. They have a good selection, don't gouge you on shipping and allow you to select the sex (though for a small upcharge). Also, you get a decent range of shipping dates you can choose from.
So, when I ordered my first flock of ducklings last year, I only could get straight runs. (Ordered from Cackle Hatchery and was very pleased with the experience) In the order, I ordered 4 Cayugas and 4 Anconas. All four Cayugas turned out to be drakes and all four Anconas were ducks, go figure...