They look great. And they really aren't that expensive for a good quality leather sling. Not to mention how well it works. I bought a nylon sling that was supposed to be easy to loosen and tighten. Never could figure out how to make it do it with less hassle than a standard sling.
I've got a Browning thumbhole sling my wife bought me for my birthday years ago that cost a lot more than the Montana models. Still going strong. Wish I'd have known about these back then.
The only Nylon slings I buy are Uncle Mike's (Butler Creek) MOUNTAIN SLING. Tough 1-1/4" nylon web with non-slip lining. Complete with permanently attached 1-1/4" QD Super Swivels to fit guns with QD studs. Wide enough for comfort...won't slide off your shoulder. Just slide the buckle to adjust for carrying or use as a hasty sling. Great for rugged terrain. Compact enough to roll up in your pocket