I don't see much comparison between these cameras for obvious reasons. They are different systems with their own set of pros/cons but how do the lenses compare wide-open in terms of contrast and sharpness? I don't care so much for bokeh.
I only care about the 50mm and I shoot at wide-apertures quite often. I have a Canon P with the 50 1.4 and a Konica Auto S2. I prefer the build of the Canon but the lens on the S2. Overall, I prefer the S2.
I want a smallish compact 35mm camera for not-that-much so I figured that a Retina III would have a better build and maybe a better lens than the S2; however, 35mm SLR's are cheap so I might ditch rangefinders for an OM1n or a Nikon FM with a 50 1.4. If money weren't an issue then I'd get a Leica M3 with a Summicron but I'm allergic to their price-tag...and I'd rather spend that money on medium format gear anyways.