David Weaver
I'm sure there is some deviation from that, but I'm in agreement after having used just about everything that practical predictable use pushes me back toward finishing with natural stones. Touch and control counts for far more than speed for grit size.

For example, when a was setting up and selling a lot of razors, I found natural stones one step coarser to be faster than a step finer synthetic. The control with razors was preferable, and natural stones at that slight of an angle cause fewer strange failures. The idea that natural stones should be discarded because they're not as fas per particle size is a false dilemma. Just step up the particle size one notch, the sharpening time will be the same.

The exception that I can think of with users is George. He likes spydercos, but they behave a lot like natural stones. He's done a lot of incredibly fine work with synthetic stones.