Best Rifle sling I have tried is Slogan. For functionally I have not seen a better product. Not the fanciest lots of slings out there that look far better. But most useful I have used.
One thing it does it stays on my shoulder without slipping better than any I have tried. If you do a lot of walking with a rifle on your shoulder give this a look. Made of rubber. Since it's a double strap sling you can strap on your back like a backpack when going over rough obstacles. The link has a video that shows the benefits of this sling very well.
http://www.sloganoutdoors.com/products.html
