My Dad owned a duck club in Imperial Valley in California for 60 years (my Uncle & cousins still own and operate it). I hunted waterfowl since I was 8 or 9 years old......70 years! I still go back and hunt with them every year. I think the easiest ducks to decoy are Spoonies and Widgeon. The hardest and most wary are Sprig (Pintail). I like to eat teal and Mallards. I remember being in a bind with my Grandfather and calling in a flight (about 15 to 20) Spoonies and each of us getting a triple (that's 3 apiece in 3 shots apiece). They were fighting a pretty good wind and just seemed to hang there, 25 yards or so away.
Biggest problem I always had was finding different ways to cook them. My wife used to say (You didn't bring any more duck breasts home did you? We still have some from your last trip.)