It depends on what you want the sling to do. If you just want something on a hunting rifle, for the odd occasion when you need both hands free, then a simple carry strap will do. A narrow one will save some weight too. For this sort of purpose I just use a plain leather strap, and there are any number of makers. Fabric will do too. One which can be extended long enough to carry the rifle across your back is handy too.

If you are one of those people who wants to be able to walk around with your rifle on a sling as a general sort of thing, rather than usually having it in your hands and only using the sling occasionally, then I guess that things like padding and neoprene and cobra-shaped sections and so on might have their attraction. These generally add to the weight swinging around under your rifle when you want to take a shot though. There are more complicated ones too, about which I have little to say other than in relation to one a mate of mine had, a Kifaru IIRC, which seemed to always end up pointing the rifle at everything he faced, including me, which I definitely did not like. On the whole I have no use for any of these though.

If you want to use your sling as an aid to accurate shooting, then you really need something a bit different. The US Pattern 1907 type does a very good job, if you know how to use it, and I have one of these in leather for service rifle competition. I also have a webbing sling which can be made to function as a single point loop for shooting by detaching it from the rear swivel and making a loop, for use where the competition rules don't permit the Patt 07. The Patt 07 tends to be a bit weighty though, and the other one not ideal for quickly setting up for a shot in the field. The other type worth looking for though, which does much of what a Patt 07 sling can do, and is better adapted for hunting, is a Whelen-type sling. This has the ability to form a loop for your arm, like a Patt 07, to steady your shooting, but uses rather less leather to do it so is lighter. I have a couple of these and they work well. I believe Hunter Leather makes them, and there are probably others. I don't remember who made mine.

Two final points: first, if you do intend to use your sling for shooting, is that it can affect POI, especially if your rifle's light and has a flexible forend. Second, if you are going to go hunting, put your sling on and have a good hard look at it, and then give the rifle a vigorous shaking. Anything that glints or rattles should be taped - a bit of tape around the forward swivel will also protect the web of your thumb.