I've got a few, just bought another one the other day (upland camo SOCOM from PSA) and I love'em all.
I've got an Art Cavanaugh built M21 that is my favorite. For those that know Art I spoke with him the other day and and he is suffering from Parkinson's ... one of the finest M14 gunsmiths to ever walk the face of this earth. Tragic.
ETA: Before anyone knocks the modern slings ... I went through the old 82nd Airborne Sniper School at Bragg in the late 70s and we used the modern green slings so that's what I prefer. The leather slings are pretty, very traditional, but not practical for operational use in humid wet environments these days. I live in The Deep South ... leather just doesn't hold-up down here (doesn't matter how well-oiled they are) except on safe queens and mine are built for hard use. My instructors were all Vietnam Vets and they all railed-on leather slings ... they're very pretty but they are uncomfortable, heavy and they don't hold up in combat environments for very long. That's why so very few WWII, Korea and Vietnam era slings are still out there.