All the mills except the Turkish mill have identical burrs, so they will not differ in terms of the grind produced. Besides aesthetics, the designs differ primarily in terms of how you load the coffee, the volume of whole bean coffee it can hold (the 169DG has the largest hopper), and the dimensions of the mill, which effect how easy it is to hold it (which is why I think the knee mills are the easiest to hold as they are the narrowest) and how much space it takes up (the 169DG is the largest). The Turkish mill has a slightly different mechanism, and from my perspective has as its main advantage its compact size, which makes it ideal for traveling/camping/backpacking.