I've just got a cheap-o (straight, non-padded) nylon sling (tan/brown) on my 336. I know it isn't much -- snazzy it ain't, but it is very similar (other than color) to the sling that I was issued on my M-16 (A1) back when I was in the Army in the '70s, before I was able to ditch the rifle entirely after I became gunner in my 81mm mortar crew. Yeah, I started out with a leather sling as a kid/teenager, but I got used to the plain ol' nylon web sling in the Army and am comfortable with it in all of its cheapness. Because it is so similar to the old stock military sling, I can use the marksmanship tricks that we were taught using the military version of it.
One thing you can say about cheap-o nylon web slings is that they are durable. And trouble free. Low maintainence. They may fray a little bit as they get older but even so they remain serviceable. They are practically impervious to weather, although they do absorb and hold on to some moisture while out in wet weather but then again so does leather. It doesn't crack or split.