Oh yes, the Daedra have a terrible reputation, and after playing Skyrim I'd have to say their reputation is completely undeserved.
It's not like any Daedric Princes require you to lure a friend to a pillar for the purpose of sacrificing them, or force you to kill an ally before asking you to rescue an old man just to beat him to death. Why, they've never once asked me to kill someone. They certainly never kill their worshippers once they outlive their usefulness. And all the artefacts they give you would never require you to charge it up with the blood of friends or dreams of innocent sleepers.
It's simply inexplicable that the Daedra have such a bad reputation. Why would anyone dislike such kind beings with such a deep respect for the preservation of life?