I actually use a Sears Craftman rotary tool. Craftsman warranty is top notch. I've seen them take back a wrench purchased in the 70's. I would go with as much variable speed as you can afford. I like the ones with a variable speed lever marked off,1,2,3,4,5.

And I must stress the safety glasses. Don't go cheap on those. At least $15 - a bargain for keeping your eyeballs intact.

Lightsaber Warning Label: "CAUTION: Do NOT attempt to sharpen blade."

http://www.geocities.com/projectstm/lightsaber.html