I recently got a Hansen cutter and it is wonderful compared to the homemade tools I had been using before. It took me about a year looking at all the different styles of cutters to finally decide on the Hansen. There are two basic types of cutters, one with a split barrel and one with a notched barrel. Split barrels include the Hansen and the Nuebert. Notched barrels include the lacemaster and Wayne Juestke's (sp?) cutter. The main selling points on the Hansen for me are:
Cutter, beveler, and splitter all on one tool.
the blade is angled instead of angling your string in a notch.
String can be cut from the outside of circle compared to a lacemaster where a hole has to be cut from the center.
It has a heavy duty splitter blade that is wide enough to handle a wide variety of sizes.
Downsides include the challenge of making small width changes to the collars and being able to set the splitter thickness for multiple strings. I have not cut enough string yet for the first issue to cause me much concern. On the second issue, I am working on a small thickness gauge based on some brainstorming with Leatherpownder.