I've been kind of skeptical of three point slings in the past (partly because the only one I'd tried was a cheap, crappy one). I stuck with a simple nylon carry sling for my rifle. Recently, however, I got a Sling System EZ Sling, which seems quite a bit better than the previous three-point system I tried. In fact, I'm thinking about upgrading to one of their higher end models.
Before I go spending any more money, I'm curious, what sort of slings other people have on their defensive/SHTF rifles. What kind of sling do you use? Is there brand/model that you find particularly good?