The conclusion from all the testing is that the Sigma, Nikon and Canon lenses are all pretty sharp at the center, but focus and constrast fall off quickly towards the edges. The exception was the Rokinon, which had a fairly flat response to the edges, but was not as sharp and contrasty at the center. Roger says that in the "outer 1/4 of the image it [the Rokinon] is as good as the Sigma, or perhaps a bit better." Depending on price and what you want, the Sigma is a strong cnotender against the Nikon and Canon lenses, and the Rokinon may be more consistent overall and just as good off-center as the others.
If you are looking for newer designed lenses for your kit, Roger declares the Sigma 35mm f/1.4 lens to be the best 35mm wide. Being full-frame lenses, these lenses should work with compatible film cameras. To keep costs down, keep in mind eBay and the B&H Used Department.