The Go-Sport Gorrila is stiffer at the toe section than the standard Go-Sport. I regret selling my standard Go-Sports but they were black and my Gorrila Go Sports are black. Had they been a fun color like blue or yellow I would have kept them. One of my usual dive buddies converted to Gorilla Go-Sports. He is convinced they are much stiffer than the standard, he wears a size medium. I do not really agree. But, he never owned a set of standard Go-Sports. I did and I dived with them extensively before switching to the Gorilla version. I do like the Gorilla better for me and pushing my camera, especially accelerating from a stop, but I did just fine with the standards. Larger people (which I am, not) stronger people (which kinda am in a weak sort of way), people pushing cameras or dragging side mounts, get the Gorilla. Everyone one else will be fine with the standard.
Just saying, but I am able to back up at sufficient speed to hang with a group. I find this useful for taking diver pics. I get out front, spin around, swim backwards snapping away. Once upon a time I was told I do not back kick or frog kick properly, my retort is that obviously you are the one doing it wrong.