I third slicing.
But you know, if you really dig shredding the cheese, a good food processor works very well. I've no experience with the kitchen aid attatchment, but I'm sure it works well too. I would get whichever one takes up the least amount of room, be it a food processor that you can use to do other things in (such as make fresh sauces) or as an attatchment to a mixer.
I have the electrolux dlx 2000 and am comtemplating buying the cheese shredder, but I do really well with the hand slicing and would rather get the blender attatchment first.