Markus, thank you for this review. It is nice to see how the top-shelf of gear is doing... I don't know whether is the material used or overall design, or both but their lenses look beautiful.
What exactly is the difference between the black anodized and black paint versions? I'm very familiar with the 2 finishing processes, so that is not my question. It's why do they offer two different finishing processes? Are there any other differences between those lenses (besides the hoods)?
The black paint version is a limited edition, which was introduced in 2000 to match the Leica M6 black paint, also called the "Millenium Edition". Leica often builds limited editions of their lenses (and cameras), which usually sell soon and normally become collectors items.
It's not that obvious in the images, but the black paint lens has a glossy finish, while the regular anodized version has a somewhat "silky" surface. Additionally, the black paint lens features red markings, while the anodized lens shows the normal yellow/orange markings.
Optically, the lenses are identical. The main difference is that the anodized version is made of aluminum, while the black paint version (and also the silver chrome version) is made of brass. That's why those two versions are quite heavy (for such a small lens).