Synthetic ropes have been dying since their initial hay day back when rock crawling comp buggies were big.
I've thought about running one but I use my winch so infrequent that the rope would probably deteriorate before I got a chance to use it.  I still have the stock 5/16" cable and I can leave it on the winch without having to worry about it too much.  Although, synthetic rope could be removed off the spool and stored inside but that's a hassle.  In any case, there are some advantages but unless you take care of your rope, you can expect a short life.  Heat, UV, abrasion, etc... can accelerate that.