The spring loaded "string keeper" on the thumb model makes it much more ideal for hunting for me as well. Treestand hunting... clip it on and let it hang. Spot and stalk... quick loading like an open hook. I switch back and forth between a resistance release for targets and thumb trigger for hunting, and really wanted to like the perfex and perfex r. They felt great in my hand, but with the short neck on the resistance, I had multiple occasions where I accidentally partially reset the jaw while loading an arrow and ended up sending the arrow about 6 feet down range as soon as I started to draw. Since 90% of my hunting is from a treestand, I wasn't a fan of the open jaw on the perfex thumb. These seem like they will solve both of those issues for me.