I have the black titanium bezel on my 170Cn and I always wondered how they made it black! I just discovered that it is AlTiN coating and my researches tell me that it is very durable.
I don't abuse my Clickys, they travel in my pocket on weekends outdoors. While the stock ss bazel of the 140C is full of slight scratches, the black titanium bezel looks like new, no visible harm.
What I really don't like is the feeling of that bezel. While bare totanium is very smooth, this is terribly rough. My lights stand on glass in a showcase, the one with the ss bezel easily slides on the glass, the AlTiN doesn't slide at alll, it would probably make an awfull noise if I insisted and perhaps leave some scratches too. The black isn't deep black, it doesn't really look like a coating, more like if teh metal absorbed some color, difficult to explain...