I like the Domke-styled ones. The Lowepro sling types are too hard to be comfortable for me most of the time, and backpack style ones don't allow you to take out or put in your equipment without first taking off the bag and laying it flat on a surface. The Crumpler slings have flaps that'll make it too awkward to open while it's slung around me (I carry my sling bags higher so it sticks to my body).