Apparently, they are supposed to be similar to Neumann KM-84.
I think almost every old condenser mic out there has someone saying THIS about it. Most of the time it's an effort to drive up the prices on esoteric and little known stuff and most of the time it's not true at all.
I am not familiar with this particular mic but as everyone knows, Milab and PML have been making good microphones for a LONG time. I wouldn't be afraid of a PML model from the late 60's. As far as I know both companies still service their old microphones, so why not give them a try and report back here with your results? I would definitely be interested in knowing more about this, but then again I'm one of those who doesn't subscribe to the Schoeps/Neumann/AKG/DPA or bust theories. I like it when an unknown mic can whup the "big boys"! That's why I became a Milab and Nevaton dealer, actually!