Pros: Funny to look at, quiet, big, really good at flying, nice eggs
Cons: funny to look at, big, randy, really good at flying, messy
We love our Muscovy drake but he is very very randy. He will try to mate with any bird he can get his beak on, which made for an awkward situation with the neighbors. He would fly out of his pen and go visit the neighboring flock. The silkies were not impressed - at a quarter of his size, he was just too rough! I had to cut off the flight feathers on one side to keep him penned in.
He's a big, ugly guy, but harmless enough to us people. You probably don't want to get him to guard any hens (he's happy to let them get eaten and just fly off -- chivalry is not a strong suit) He's let 2 different mates get gobbled up. When his Muscovy mate was around, she laid nice eggs.
I would not say he is friendly, but he is not unfriendly either. He's done fine with just a little pool of water, so he would be okay if you do not have a pond. He doesn't want to be held or pet.
Every time he molts more feathers come in white. When he was a chick, he was entirely a beautiful green. Now he is quite a weird looking guy.
People are always shocked when they see him and want know what is wrong with him. If you want to have a conversation piece, go for a Muscovy.