They've been discussed, but I don't know anyone that has ever run them or done a comp between mbhos.
That said, I am going strongly urge you to avoid them. You will save very little versus genuine mbhos and sacrifice a lifetime warranty. As good as mbhos sound (in many situations, I prefer the ka200n capsule over anything else), the build quality is subpar and they will need to go back to the factory for servicing at some point. I have personally witnessed a pair of 603s and two! pairs of ka200n's that have demonstrated serious issues. Luckily, all you have to pay for is shipping to the factory in Germany and be willing to wait while they are repaired.