Upload & Sell: Off
After having owned many 50's in the last 35 years. - Nokton 50/1,5 Cron 50-R, and an assortment of Takumars, Fujinons, Rokkors, Canons and Nikkors- I've kept only a battered Kern macro Svitar 50/1.9.
I don't know if it's the close focusing ability, the lack of CA or the very special bokeh. but I'm not interested on any other 50mm. be it a Noctilux, a Cron Apo or whatever.
That goes to show how personal the choice is, and probably also the reason for many of us to own more than one single 50mm.
I had the Macro Switar 50/1.9 (which is not the same at all as the cheaper 50/1.8, just in case somebody wonder) and enjoyed it. In the end I sold it as I didn't like the flare and low contrast in some situations. In a comparison shot matching it to my Zuiko OM 50/2 Macro it did very well, less CA (all sorts) for example, but I prefer the bokeh from the Zuiko.
In fact, the OM 50/2 Macro is still my choice for a very, very good alt 50mm. The Switar, the Summicron, the Summilux E60 as well as the E55, the Zeiss C/Y and some others all had to go. Now that I use an E-M5 I'm reasonably happy with the micro Zuiko 45/1.8. I have the Zuiko and a 60m Elmarit-R Macro in a drawer and I hope I'll be able to use them when returning back to FF some day.
So, OK, my vote goes to the Zuiko 50/2 Macro.