I like the regular attack directions personally, if I move my mouse right and left click I think of it as my guy chambering his weapon to the right of his body, and then when you release, you follow through the swing (like a wii-mote like other people were saying with inverted). Seems very intuitive to me.
Inverted mouse controls seem like you would be out of position a lot, like if someone is to my right and I want to swing from left to right, I would have to move my mouse FARTHER right to chamber back my swing, and then move my mouse right again to follow through the swing...