Absolutely second oldracer's point(s). A sling strap is less about where the strap attaches to the camera than how it sits on the shooter and how the camera moves. This c-loop just takes a traditional strap setup and moves the attachment point to the tripod socket, which may be a good thing, but its got very little to do with a sling strap. A sling is worn over the opposite shoulder (the left for a right handed shooter) with the camera resting down around the right hip (higher or lower depending on individual preference). So the strap goes around the whole torso from left shoulder to right hip (or reversed for lefties), rather than just around the neck. And the strap barely moves when you lift the camera with a sling strap - the camera just slides up the strap to face level. And then slides back down to the hip.
With a sling, I personally prefer a tripod attachment point because I find the strap is always in the way of something when I use a lug-mount attachment point. But plenty of people like them there, like oldracer. So I guess that same issue can come up with a more traditional neck strap and the c-loop addresses that, but it doesn't make a regular strap into a sling strap at all.
So it looks like a useful product for folks who like a traditional strap but don't want the straps attached at the lug mounts, but that's about all.
-Ray
