I am of the opinion that such complicated and expensive sharpening systems are gimmicks and not needed to sharpen a knife. You can sharpen knives to hair shaving sharpness freehanding your edge with several 8 inch stones and use a magnifying glass to see what you are doing to the edge.
I use a Coarse DMT 8 inch stone with hard steels such as D2, found I can use a medium India stone on 1095, and the most important sharpening tool I use is the magnifying glass on my Victorinox knife
with this magnifying glass I can see if the bevels are flat (which means I am not varying the sharpening angle) , that the bevels are even, and the edge is centered in the blade. You calibrate the consistency of your blade angle by looking at what you are doing to your edge. Incidentally, for most knives, the sharpening angle changes depending on where I am on the blade. The curved point area I sharpen separately from the flat edge, and blend the bevels at some intersecting point. When the bevels are even I get off the diamond stone. My fingers tell me where the burr is, then I go a medium or fine India stone to knock the burr.
It does not take much to remove the burr. No more than a slight polish, hard steels, such as D2, are hard enough that extended strokes on a non diamond stone will round the bevels. I feel the keenness of the edge with my fingers.
After that, the edge is sharp. Sharpen enough knives, and then cut things, you will develop your own opinions on what is an appropriate angle.
My sharpness standard is a Roma tomato. If I can effortlessly cut a Roma Tomato, the edge is sharp.
An advantage to free hand sharpening is that I don’t have to buy expensive specialty stones, which when they become unavailable, you have to toss the fixture. Eight inch stones go back more than 100 years, and I am sure, will be around long after me. I have had this AG Russell aluminum base since the 1970's. Still works.
