I don't have the GM version to compare it with, however I do have the Canon 135 f2 L lens to compare it with. Every time I used this lens, I knew the IQ would be top notch, sharp wide open, good contrast, smooth bokeh. Build quality is also excellent. The color is on the neutral side. I like the size too. It's fairly compact and discreet. Coupled with excellent IQ and it being a good "value", esp on the used market, it's a must have in the camera bag. The only issue I had with this lens is that one a APS-C camera (1.5 x 85mm = 127mm FOV), I find that I don't really use that field of view as much. 5 out of 5.




