I picked up a pair of the black ones recently. They are IIRR made in a different factory from the white ones. The paper/mylar membrane on those seems inferior and most I have seen on sale, including mine, have holes and tears in them.
Where the membrane is still intact, it seems quite worn and perished and not long for this world. I am probably going to replace the driver units from a donor white pair and live with the colour mismatch.
They are also quieter than the white speakers, since there is a limit to the power the USB amp can muster, even with its increased voltage.