Robert Hazelwood
There is probably a fairly wide range of densities under the soft ark label, being the middle ground of the range. Density basically controls how fine a stone can get once the surface has worn in- denser being finer.

When I bought mine, in about 2016, I considered two vendors- Dan's & Natural Whetstone. I was following David Weaver's advice on this since he has owned most all of these stones at some point or other. What I remember is that according to him the Natural Whetstone was faster cutting, slightly coarser than the Dan's. Not sure if due to density or as-shipped surface finish. For what I wanted out of a soft ark the Natural Whetstones sounded better, and was a little cheaper as well.

I've been really happy with it. I suspect the Dan's would be very good, too. You can also consider "Hard" arks from various vendors, if you want something a little slower/finer. You can always make an ark more aggressive by abrading the surface a bit with a diamond plate.