VG-10 has been in constant use by Spyderco for the better part of the last decade, they aren't hiding it what so ever. Al Mar, Moki, Kershaw, and some others also use VG-10 in some amount, again out in the open. From what has been stated on the forums, specifically by Sal, the foundry that produces VG-10 does not export it. I don't recall if it is due to Japanese exportation law or what. Kershaw can obtain it because KAI is a company based in Japan, they can also source ZDP-189 and other steels normally reserved for Japanese production.
As for the sharpening, I would say that VG-10 is one of the easiest steels to get an edge on. I would also guess that those people having difficulty and making claims of difficulty are unskilled in sharpening, have a lack of technique and patience, or are using the incorrect equipment. In my experience the edge retention is less than that of 154CM in similarly sized knives from Benchmade. Paperboard, posterboard, and cardboard will kill the edge on it faster than anything. It could be the thinner stock or something else, who knows. It's a good steel, but far from my favorite.