I was just surfing 4WD & Sport Utility's website and came across an article on synth line.

Rockstomper also carries synth line for another source other than Masterpull which is in the article.
I have the Masterpull on my winch.

 

If you are in the market for winch line I reccomend the Rockstomper over the Master Pull. I have the Rockstomper line on my winch. The Rockstomper comes with a 10 foot Nylon sheath to protect the line from snagging on rocks or trees. This sheath is the perfect size to allow the line to slide through while not being so bulky that it won't spool in and out through the fairlead without bunching up and being a pain in the A**. If you compare the Rockstomper nylon guard with the Master Pull, you will find that the Master Pull is too short, too bulky, and not included in the price of the line. The Rockstomper guard is longer, slimer, and included in the line purchase price.

Rockstomper Winch line page.

Master Pull page (Look at the winch line page linked on the bottom left)

With Master Pull a hook is included and the sheath/ guard thingie is not. ($8 extra for 3 feet) With Rockstomper the guard thingie is included but the hook is not. Rockstomper is cheaper. (Additional guards are $5 for 10 feet.) If you have a winch, you have a hook that will easily fit the RS line. With MP you have to buy a hook that you probably don't need. If you need a hook, RS will sell one for an additional $15.

Either one is easy to use and much safer, lighter and more user friendly than steel cable. Apart from the hook, guard and price, and available colors the 2 are the same. Check out the Yotatech gear reviews section for more.