Pekins are the most eaten because they grow quickly, large, and efficiently and the white plumage makes them easy to pick and gives a clean carcass. I personally think Pekins are too fatty. BUT I havent ever pasture raised my own, they could be quite lean if raised on pasture I suppose.
Muscovy are delicious, and they are leaner than Pekins, and will hatch MASSIVE clutches and make excellent mommies reducing the need to artificially incubate of brood offspring. I have yet to have a Scovie hen NOT go broody, they will try and try and try all season. If you like fatty duck, Pekin is probably the way to go, but if you like lean meat attached to personality filled little dinosaurs Muscovies are for you.
They DO fly VERY well, the girls do anyway, the boys are typically too fat HA!, BUT you can simply clip flight feathers, this is completely painless for the duck, and they will be grounded till the next molt. It can be a challenge, and painful for YOU, if you don't have friendly ducks to clip feathers.
Down side, even with winter lighting, MY Muscovy hens only lay seasonally during breeding season and are not keen on being broken up or laying again after a hatch. We probably only got 60 or so eggs per hen all year.
We have Muscovy and Ancona ducks. The Ancona keep us in a constant overflow of eggs, as well as ducklings to sell, we also butcher culls, and the Muscovy keep us in an overflow of ducklings to grow out and butcher, as well as providing our incubation and brooding. If we end up with the room in the next few years we will add Silver Appleyards, mostly because I think they are beautiful and for the conservation end.
It is really about what is more important to you. You might try a small number of a few types to start off and see which you like best. If you have the room, that is what I suggest. That is what worked for us. Best of luck!