Rokinson, Samyang and Bower are they all the same?
"Samyang SLR lenses are also branded as Vivitar, Rokinon, Walimex, Bower or Pro-Optic."
You do have to deal with different customer support channels in the case of a warranty claim or repairs. Bower charged me $200 for a replacement for my dropped 35/1.4 (which is horrifically delicate, by the way), and when the lens they sent back was unsatisfactory they replaced that one for free.
From what I've been hearing, even from a fellow who rehouses still lenses for the motion picture industry, the Rokinon 35 mm 1.4 is quite decent. I wonder if that holds true for the 85 mm 1.4 ?
I've heard that the 85/1.4 has great bokeh, but never hits full sharpness.
If you get lucky, the 35/1.4 is insanely perfect, but as I've experienced, many are far from satisfactory. The second copy I had (the first replacement lens) had a tilted focal plane: if the center was focused at 8 feet, the left side was focused at 9 feet and the right side at 7 feet or so.
But I doubt that choosing different brands of the same lens will get you copies with different levels of quality control. Unless Bower just sent me crappy lenses as replacements.
I have the Samyang 85mm 1.4. It is a great lens and a bargain. Wide open though has narrow DOF and can be tough to get accurate focus but when I get it right the bokeh is peerless. The sharpness is excellent at wider settings.