For half the price and sharper results than the EF counterpart, I have zero complaints on this lens.
My only complaint about the Takumar is that now that i've got the FL 55 f/1.2 and EdMika adapter, which one do I use?
I would have gotten the 1.2 if I was affordable. Haven't used it before, but I can't handle that shallow depth of field while manual focusing, so I'd stick with the Takumar.
Did I mention the Takumar is L lens sharp at 5.6?