Well, as far as selling birds for profit, you can make more on ducks. They're both easy to raise, you don't need a pond or pool for ducks, but they sure do love them if you do! We had a plastic cement mixing pan for ours, and they loved it. From what I heard, Muscovies are super producers, great mothers and all that, and reproduce super fast. The eggs to me have a bit of a strong taste, but they're good for baking and frying. As far as plucking, unless you have a whizbang plucker or something, plucking ducks and all waterfowl by hand is a real pain...they got two sets of feathers, the regular ones, then the fuzzy ones all over their bodies. I hand pluck birds, and chickens are super easy to clean vs ducks. Geese, man those are even tougher than ducks unless you know how to singe the hair off or dip it in a hot water bath, but you got to get the temperature of the water right. The only duck I had was those white chinese, and she was MEAN.

There's some federal lawstuff going on with Muscovy you need to be aware of if you're going to get into raising them for profit. The government outlawed raising Muscovy without realizing how many domestic Muscovy breeders there really are. It sounds like it will work out but for right now, it's actually illegal to have Muscovy in captivity, as crazy as that sounds. This is brand new, like just a few months ago.
Anyway, thought you should know.
I agree, raising ducks would be far more profitable per pound, especially free ranged on pasture, since they are such good bug eaters. The food is more expensive (higher protein) and I think the little chicks are a little harder to raise, messier and require more bedding. But, with the right set-up and market, the profit margin should be there.
There is not much profit margin in chickens. They eat a lot more than you can make, even free-ranged, jumbo-cross organic meat butchered at 6-8 weed. Feed cost is really high right now, too.
The best profit margin I've ever had in poultry, crazy as it sounds, was when I sold peafowl and guinea chicks. Free ranged the adults, collected and incubated eggs and sold tons of chicks during the spring and summer.
They were very popular where I used to live, in SW OK, for some reason. I'm sure ducklings would have done well too, and when I move back to the country, I plan to add some duck varieties to my little hatchery plan.