I remember the days when I wrapped Aliplast around the ends of a surform to protect my fingers from getting cut by the edges. I jumped at an opportunity to get a surform holder from Coyote because it looked like a slick widget. I found, though, it is much more than a gadget; it actually lets you work more efficiently.
One of the main reasons the holder was developed was to allow an increased amount of force on the surform, resulting in the removal of more material. If you are still hand modifying your transfemoral models, this is a must have. If you are looking for something that not only protects your hands but also allows you to modify faster, this is what you need.