Cool. I enjoy the heck out of sling shooting. Watching a true "high master" long range rifleman work a good bolt match rifle is impressive. I shoot with those guys, and actually did earn my LR high master card, but I'm a long way from the top of the heap. I've also taught sling work to a number of LE/SWAT snipers over the years. Dad taught me how to use a sling. He was a match shooter in his day. The Marines really hammered it into me too. They still know how to shoot a rifle!
Where I really like the sling is in the field - it gives me another option, and a good one. A few years ago I made a 180 yard shot on a bull elk. Not a long one, but through a smallish "window" in the tree branches. Prone was too low, or I'd have rested the rifle on my backpack. The only thing that would work was a good solid sitting position. I took the few seconds needed to wrap my arm in the Turner sling, got into a good sitting position, steadied down and torched off the 7mm Rem mag.
The 175 Nosler Partition went where it was supposed to go. The bull took a few faltering steps and that part of the hunt was over. My hunting buddy was ecstatic about the shot, and I admit to being pleased to have had the skill to pull it off.
If you want an alternative to the traditional sling by Turner, take a hard look at the nylon shooting slings by Mike at Tactical Intervention. Wow - quite a sling! I don't think there's a better shooting aid than Mike's M24 quick-cuff sling.