I remember watching a video by Ken of the Youtube channel Theoria Apophasis in which he says this optic beats any other M42 mount 50mm lens.

In terms of sharpness, I completely agree. This lens is incredibly sharp at f2, it rivals G Master glass, even though only in the center, until stopped down. But there are also other Tomioka made Yashinons  that produce the same level of sharpness at f2 (Auto Yashinon DX f1.4 and f1.7 for example), yet with a different kind of rendering.

As for character, the rendering of this lens is very, very unique.

It produces a "swirly" background blur, a little similar to the Zeiss Pancolar, but in general, I would define its bokeh as "dense", especially when shooting wide open. 

The overall image is very strong and full of character, whereas the Zeiss feels more "gentle" and balanced overall in my opinion, still having its own distinctive rendering.

It's such a shame this lens doesn't have a smaller minimum focusing distance, but because of its outstanding sharpness, it's easy to crop in without losing too much resolution.

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Why use the Yashinon 5cm f2:

1) Superior sharpness

2) Beautiful colors and black and white 

3) Full of character

4) Light and compact

5) Sturdy, exceptional quality construction, made by Tomioka Kōgaku K.K.

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Weaknesses:

1) Minimum focusing distance of 0.55m

2) The flares this lens produces can be invasive unless used artistically

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