I've had a great experience with Indian runners. They remind me a lot like penguins, standing up and waddling.
They can be tame, if you make them tame.
I have had four indian runner ducks in with my chickens, and I have a large pen (bigger than 125'). They can move pretty fast when they're startled, but you can always corner them and catch them as they don 't fly. And you don't have to worry about being bit-they don't have teeth to bite.
As long as you have a place for them to hide or get away from sun to cool down, even a little or old dog house would work, some grass/plants for them to eat, a little kiddie pool or small rubber maid container (with rock inside so they can walk out) they'll do amazing. They are smart devils, stay in packs and are pretty easy to get one moving. The rest will follow!!
If your up for free ranging your ducks, you can always supervise them little bits at a time so you and they know boundaries and safe zones. They catch on quick to where the food and water is, so they'll go back when hungry/thirsty. I let mine out with my chickens, and my ducks just follow the chickens around grazing. Sometimes chickens go too far and ducks just lay in the shade. Other times the ducks and chickens get herded back to safe zone because chickens have gone too far.
You'll love it, love them!!! and get the hang of things your own way. Do what you feel comfortable with at first, then loosen up and try something new for them. Treats, snacks, some new food/water. They love it all!
Pros: quiet, calm, relaxed, not a lot of time is needed to take care of them, foragers, don't take up a lot of space so not a big pen is needed (dog house would work!).
Cons: needing water dumped at least once a day, needing pool dumped and scrubbed at least once a week, a little messy when eating food and water (try not to put any water pails/source in the pen with them as they will find a way to swim in it and poop in it).