I went thru this myself. I didn't buy any of these lenses. (Now I do own a Zeiss 21mm 2.8..so I am not totally opposed to manual glass...love this lens!)..but for a 50mm which is a workhorse, everyday-use lens, I needed and wanted "fast" AF. I ended up buying and loving the Sigma 50mm f/1.4. I researched the 3 lenses you are looking at and also the Canon f/1.4. In the end ( I NEVER thought I would own a Sigma lens, trust me) I bought it for a number of reasons. The fast auto focus, the fast f/stop and the "quality" of the bokeh when the lens is wide open. All my other lenses are Canon L lenses (except for the Canon 15mm fisheye). I own the 16-35mm II, the 85mm f/1.2, the 100mm f/2.8 Macro IS, the 70-200mm f/2.8 IS II and 1.4x III converter. I sold my 24-105mm in anticipation of the release of the new 24-70 f/2.8 II...and got caught holding the (empty) bag when Canon changed the ship date...but I will own that lens upon its arrival.
That being said...I do not think that the Sigma is a compromise in any way. I just got a 5DMkIII (but have not used it much yet)...so my references are from the MkII. I have found the Sigma to have good autofocus, great bokeh wide open (a little soft but all of these large aperture lenses are not their sharpest wide open)..and with the aperture closed down a little the lens is AMAZINGLY sharp. Really. Also...I found the Sigma to be less expensive and not as much of a beast to tote around like the Canon 50mm f/1.2, an yet the Sigma "approaches" that lense's bokeh. (I think that the Canon f/1.2 lens may auto-focus more slowly, too, than the Sigma..but I could be wrong on the point..not sure) The Sigma has the best balance of all of these lenses for me. I know that everyone's shooting style and needs are different...so this may not be the prime normal lens for everyone, but I have been very happy with my choice in this area.