I've turned to mix-mix, right now, I agree it is very often abused, I saw a very talented member, who helped out and was king, had -20 Karma, I reviewed the posts, and there was nothing wrong about them.
It also can be quite intimidating if you think about it, some person might have around 20 Karma, while the others, have around 9 (like me)
On the other hand, it might make it easier in choosing future MotM, not only do the moderators/admins look at how they post, I believe they are also chosen by their stats. :3