After searching for a properly documented test on all important apertures for the Hex limited but with no luck, I finally decide to contribute my bit for this wonderful lens. All shots were taken with support (but not tripod) and focused as well as I could. Hope this set of info will help to be owners of this lens reach a conclusion:
Harshness was less of an issue than it's tendency to flare and produce secondary reflections in adverse lighting. The extra speed of the Hex is also nice to have with lower than usual corner light falloff. The only thing I'll miss is the 'cron's incredible edge to edge sharpness even when shot wide open.