Other options for slings:
Larry Vickers - Blue Force Gear AA Padded 2pt Sling - one that I use the most
Viking Tactics V-Tac-Mk1 or Mk2
Magpul MS2 Sling
MS2 - one of my favorites, at least until they come out with the MS3
Keep in mind that slings, are a lot like grips and stocks. One size does not fit all

Also, some of them are a little "noisey" with the hardware, so if stealth is an issue, you may want to take a look at how the sling is mounted to your SUR, or what options they have for the particular sling you are looking at. So you may have to try a few different styles to find the one that fits you and your needs the best.