Truth be told a good set of diamond stones are a small part of the equation. The biggest is the person who is using it and their skill with what their using.
What do you want to sharpen with benchstones, crock sticks, guided set ups, powered setups, etc.
Benchstones: easiest recommendation is a DMT 6in 4 grit, 2x double sided set that is in a wood box. A Google search should get you the link.
Crock sticks: Lansky diamond turn box, AG Russell crock sticks, Sharpmaker with diamond/CBN rods, a d probably a few others.
Guided setups: Lansky, gatco, wicked edge, DMT aligner, edge pro, KME, work sharp (various models)
Electric: worksharp Ken onion edition, paper wheels, and a few others out there as well.
Washboard made by one of our members and scary sharp method are both two other things to look into.
Lots of options and don't forget you can get angle guides for the be benchstones.