I recently got the MF-2 adaptor, so yesterday I tried my hand using the 50mm f1.8 lens off my old Olympus OM-1.

Manual focus really good. In most cases it was very obvious when it was in focus, and I only had to use the focus magnification some of the time.
I've posted some pictures here http://www.flickr.com/photos/ajshepherd/sets/72157622221287627/ although this is my favourite:

It's so sharp where it counts.