ORIGINAL: stealthycat II
I've owned just about every type of broadhead sharpener available - and they all failed except one.
The only one to get is a KME
http://www.kmesharp.com/
I have one, the broadhead one, and its absolutely the best ever made. Some people say they can get heads sharp - they don't have the same definition of sharp that I do.
I looked at those and I have GOT to get one. It looks like it could even be used to sharpen the blades on a Grim Reaper. If I could get the Grim Reaper blades truly sharp, it would take care of my only issue with them.