I have run a few and played in a couple of evil campaigns over the years. It is not my first choice for fantasy. I want my fantasy to be Good. (The ones I've played in have all been modern or futuristic.) In my experience, many of the players who want to play "evil" really just want to be jerks.
That said, it can work with the right group and the right setting. Just because you're evil does not mean you're so greedy or violent that you're stupid. Evil does not necessarily mean psychotic. Face it, there are people in modern society who would be classified as "evil" under D&D guidelines, including a number of leaders who would definitely be "lawful evil".
When I run an evil game, I do put limits on what characters can do. I do not allow carnage for the sake of carnage. (One of the reasons I will not play White Wolf games with certain people.) I also point out that since the D&D world is about heroes triumphing over evil, if the party makes too big a target of themselves they will quickly become the target of someone else's adventure.
I am actually currently running an evil game because it was requested by the players. They wanted to do kingdom building. They're mostly lawful evil. The stronger voices in the group are opposed to "psychotic evil" or "lawful sociopathic", so that should help keep things from spiraling too far. Mostly they're not about being a jerk for the sake of being a jerk, they're about being able to squeeze the most out of the land and being able to be a jerk to their enemies when need be. Currently they're just getting settled into the lands they inherited and are working hard to make the locals like them, so they're really not being evil at all. Yet.
We'll see how it goes. I'm betting 50/50 that the party gets in its own way so much that they sabotage all of their own plans without the "good guys" ever having to worry about it. That's not so much them being evil as just them being gamers.
