I own and have used most of those mentioned here, and really like the Butler Creek and Op-Tech ( http://www.istdesigns.com/product_info.php?cPath=4&products_id=28 ) style padded slings for HEAVY rifles.

However, for a leather sling fanatic like me, I have grown to dislike the military styles, brass claws, difficult clumsy adjustments, weight, etc. I have found a great sling hand made in Montana by a professional Trapper that carries and uses his rifle every day. Most if not all Government Trappers in Montana use his slings exclusively,and have for many years.

It is made of a single piece of leather with no bucles, clips,etc, it is light and simple, adjusts extremely quickly, and includes a very high quality set of swivels. The link is to a product description and photos. http://www.istdesigns.com/product_info.php?products_id=6

Best of luck in your search to find your favorite sling.