The version I have is the two sided 1000/6000 combo, I love the King 1000, but as mentioned before, IMO the utility of the 6000 is limited. These get sold as a refine/finish combo for woodworking tools, but the truth is that the 6000 side isn't particularly good at that job either, even with trailing stroke grinding on high carbon steel the edges are poor compared to other stones in the same grit range and it dishes *very* quickly.
The thing to realize with stones is that similar to other aspects with knives it isn't so much there is a good/bad as that there are particular applications. If you take a fillet knife and use it for general utility you can struggle, but it isn't because it is a bad knife, just that it is bad for that particular use.
A "soft" stone has a weak bond and breaks down quickly. These are meant to :
-grind very abrasive steels
-cut with very low pressure and speed
-produce a heavy slurry and produce minimal burr formation
If you are cutting a steel like S90V for example the very hard carbide can be harder than the abrasive in most stones. If you try to grind it with an India stone for example then the India stone will likely soon stop cutting and start burnishing. The bond strength is far too high for that application as grits won't release and they just wear, round and stop cutting.
A very soft stone like the 6000 king is designed to cut steels like M2, very large contact areas (so pressure is minimal) and to grind a small plateau on the very apex to provide high durability in chopping contacts, common for paring chisels for example. For other applications, like sharpening a chef's knife in a simple stainless steel, it works horribly as it is has the opposite set of properties desired.