Best bang for buck - Magpul MS4 Dual QD GEN 2 Multi-Mission Sling

As long as your gun is set up to receive the QD push-buttons and doesn't require you to purchase adapater sockets, this is the best QD sling for single and 2-point mounting you can get for the price, in my opinion. It converts effortlessly for the two positions I carry my rifle in: Single point for active ready and 2 point for patrol/moving. It might not work well for someone who is really big and decked out with a lot of gear without some kind of an extension. I'm 6'2, 215 and it fits fine around my plate carriers and magpouches.