But its also really depend what you like and how you like your edge.
I think your right maxim, I think how you get to that edge also matters with natural hones. How sharp an edge can get and how long and easy it is to achieve are big factors for me, but then that depends on the users skill and experience, If I had a natural hone that was soft but was easy to achieve a very shaveable edge, I would be more than happy with it.

The jnat that I bought from you is a very easy jnat to hone on and gives great edges which I'm sure I haven't maxed out even yet.

With Naturals It all comes down to perspective... A 'fast' jnat may be just 'medium' to another user and because there is so much variation in naturals, it confuses it even more. The experienced users of the stones have a better view of the whole spectrum of stones like yourself maxim with jnats or Bart regarding coticules.

I have only ever used 1 jnat and two coticules so can only describe them in comparison with each other, so when it comes to speed I talk in minutes of honing, but as a user becomes more experienced, other factors like feel, ease of honing, aesthetic qualities and learning curve come into play with naturals I think. How hard a natural hone is - as you mentioned - is more important on jnats than on coticules as coticules seem to show no correlation between speed and how hard the coticule is.