I always look for projects that are risky and ones that want to do something unique. If audiences don't like it, you feel good knowing that you were brave enough to do something original. If they do like it, you feel like everyone is rewarded, because we all got to see something new.
Whenever you're playing somebody who is, by all accounts, rotten, don't focus on the rotten stuff. That stuff will take care of itself. It's already in the script; the audience is already experiencing it without you having to add an extra feel of evil. Just play them like regular people.