I haven't used one of the Worksharp sharpeners, but have a buddy that was interested in one and showed me a video on them. The system is basically a small version of a belt grinder like I use to make knives and put the edge on a knife. It looked interesting to me and my buddy bought one.
He's really liked it and has gotten to be proficient with it on different types of blades. That being said, I'm the type that likes to sit down with a stone and work a nice edge by hand.
Different tools for everyone, but I think the versatility this one gives a guy, without buying a full on grinder and all the belts, etc., is pretty cool if you are sharpening a number of items.