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I have both the K and A. The A is signifantly much sharper than the K, but the K has smoother bokeh.
This inverse relationship seems to extend across other brands, generally. The sharper ultra-fast 50s are generally sharper due to over-corrected spherical aberration, which results in edgier, sometimes "nervous", sometimes plain "ugly", bokeh (ie. not smooth, and yes I realize bokeh beauty is subjective).
The rules change when the lens design creeps away from the 50mm mark, which is why we have several examples of fast 55-58mm lenses which strike such a good balance between sharpness and smooth bokeh. Porst 55/1.2, Contax 55/1.2 100 Jahre, Canon FL 55/1.2, Noct-Nikkor 58/1.2, Rokkor 58/1.2, Konica Hexanon 57/1.2, etc. etc.
Some might argue that they like the "sharp 50mm bokeh" better. Granted, people have different taste. I am merely making the observation that it is difficult to find a sharp 50 with creamy bokeh, and much easier to find a sharp 55-58 with creamy bokeh, regardless of manufacturer.
The Zeiss lovers might just ask themselves why Zeiss strayed away from 50mm for the 100 Jahre f1.2; I think it is obvious if you compare the 55/1.2 bokeh to the two Contax 50s.
Minolta, Canon and Nikon users can make the same comparisons between the respective 50s and the "slightly-longer-than-50" lenses. The trend applies seemingly universally.