Upload & Sell: On
jbourne -- What I don't get is this: You have the EF 50/1.4, which by general consensus is a much better lens (including imaging) than the 50/1.8. That seems like a no-brainer to keep the 50/1.4 and sell the 50/1.8.
But then, in a different thread, I see you looking (hoping) for a sub-$100 Alt lens that will top other current Canon offerings for IQ. That's just not going to happen. I see you are leaning to the Pentax 50/1.4 in the M42 screw mount to use with adapter -- I've owned that combo and don't want to tell you "no", but -- that lens will not beat the Canon EF 50/1.8 for image quality. Plus, as you know (because you've mention your owning cheap Russian and East European lenses in the past), these all manual lenses are a PITA to use for general photography.
I say keep the EF 50/1.4 and stop your Alt search until you can afford some quality lenses by makers such as Zeiss.
That is, unless you are just goofing around and excited and want to try everything! Then go for it! But be clear about what you are trying to achieve -- high quality images, or just try out all sorts of gear. I've been down that road, tried a lot of manual focus lenses, and come back around to the joys of modern Canon products. Far be it from me to stop anyone else from trying!
My experience has taught me that there is no magic bargain lens the produces amazing IQ -- if it existed, someone has bought it already.
Have fun with your new 6D!