I buy all my wheels from AliExpress or eBay. Resin embedded diamond included, even for HSS. I haven't seen a need to spend on CBN.
The problem with Chinese wheels is that they don't do CBN (at least I haven't seen any real CBN for sale). I saw CBN being used interchangeably with diamond, but when probed further these were always diamond wheels.
For cup diamond wheels I agree, there is no better value for money than Chinese. Even if you have to true them up yourself. If you want good quality diamond wheels, both cup and edge, NOS Ukrainian and Russian(less of them these days) show up on ebay from time to time.
For diamond cutoff wheels for carbide (20 thou thick etc), there is a company in Lithuania that makes them, that is on ebay. They ship worldwide cheap and their wheels are first class.
I wish there was a source for CBN wheels as cheap as Chinese diamond wheels. I got one Russian CBN cup wheel long time ago.
Of course with the low cost of diamond you may not see the need for CBN especially for a hobbyist that doesn't mind taking his time. For me, I like to take my time, but I also like to push my tools to the limit sometimes. I like to get very high material removal rates on my lathe/mill/grinders if I can. And for that a CBN wheel for tool steel is simply better. You can push it harder without destroying it.
