This lens is super easy to focus wide open. It opens up the possibility to vary the aperture from (say) 1.0~8 in open shade. This makes taking photos of people very easy, and the results can be wonderful. It works well in color and in B&W.
I have used it with my M9 and my M10. The main difference is the buffer in each camera. With the M9 I take one photo and then I take a deep breath, waiting and hoping that the M9 will not shut down due to low battery ... etc. Using the M10 allows quick back to back photos. The M9 has nicer looking colors, though.
The OOF looks very attractive. It should be in almost every photographer's camera bag. Maybe 🙂