Easy to keep, we've continually raised birds that win grand champion at the county fair with very little effort. Lay big & tasty eggs and taste good themselves. You will have to touch up their water-bowls often as they like to bath in it, and spill a lot. We don't worry about having crystal clear water for them, just as long as it's not too dirty (we need to change waters very often with how many ducks we raise). You might need to space the waters out to avoid a big muddy mess in your yard (we keep a lot of ducks and the coops are spaced close together, so that might just be our problem - most ducks tend to stick around their home turf but do wonder a little bit). You'll probably have at least a few holes in your yard from the beaks of foraging ducks.
Some can be noisy - we've found that it really depends on breed and even what batch of ducklings your ducks came from. We've had two different batches of the same breed, from two different sources, whose behaviors were the polar opposite. Ducks can get noisy if something freaks them out or makes them uncomfortable - dogs running by, large raptors flying through nearby trees, etc.
Something I'll warn you about - if you have a poor male-female ratio some of your ducks may transition over to the opposite sex (this is most prominent in Welsh Harlequins) - totally normal. You'll see females mating each other even if you're ratio is right - normal and a dominance/practice thing for them. If you see males mating each other - you better throw some more females in. A male without females can be found mating chickens, geese, dogs - you do not want that!
