I really like the Olympus OM 200mm f/5, although I believe I have a multicoated version which is fairly hard to find. I know some prefer the f/4 version, but I couldn't notice enough difference between the two to warrant going with the larger f/4 version. I was willing to sacrifice speed for a smaller size.
Here's a comparison I did with the C/Y 100-300mm if it helps.
