If you're sharpening steel such as S110V, S90V, S30V, M390, 204P, 4V, 10V, 3V, Z-ware go with the diamonds.
If you're sharpening steel such as 1095, VG-10, 14C28N, AEB-L go with the standard stones.
It's not that you can't sharpen the high end steels with the standard stones, it will take a lot longer to do so. The diamonds are way more aggressive than the standard stones, so you'll have to be careful not to take too much steel off. I learned to apply less pressure using the diamonds.
You can get a fine edge with any set of stones you get, it's just a matter of mastering the sharpening system you have.
I've had one bad experience using the really course diamond stone. Small chunks of the blade actually ripped off the edge of a custom fixed blade in Z-Ware that had a good heat treat. Could have been operator error, but I'll never find out. Decided then it may take longer to re profile an edge, but at least I'll have all the metal there.
From what I hear, the CBN emulsion will give you a fine edge.