I would without doubt buy some diamond plates for anything with more than 4% Vanadium. As Kwackster has posted, nothing but diamond and CBN will properly shape the carbides.
That said, I do like my Shapton Glass stones for sharpening folders. I have sharpened most high end steels with them and didn't notice any lack of edge formation like I have noticed with other waterstones on high Carbide steels. They easily plow through steels like S35VN and ZDP but do show a slowing of cutting action on S90V and S110V, although still producing proper levels of sharpness for the stone used.
I have stopped them in their tracks with CPM-10V though. I can get the 500 to produce a decent edge although it feels like a 4000 grit edge once done with about the same polish. The Apex has all the characteristics of an abrasive that failed to do the job though, excessive burring, lacking keen sharpness, and as mentioned, an excessive polish for the grit level.
I would still recommend some Shapton Glass stones like the 500 and 2k but I would also recommend a Coarse DMT and a balsa strop with 1 micron diamond for your high wear resistant steels. That one diamond plate and strop can produce some wicked edges on high carbide steels and provide awesome cutting power.
