I am a fan of the synthetic rope. Below are my perceptions of advantages and disadvantages.
Advantages:
1. Weight. The line weighs next to nothing, and going with synthetic rope means you can switch out the heavy roller fairlead with an aluminum hawse fairlead, which weighs very, very little in comparisson. Total weight saving is about 45lbs or so, which is a lot when its sitting on the very front of the Jeep. I changed to systhetic and an auluminum hawse fairlead on my '06 LJ and the differences in ride and perfromance were both noticable.
2. Safety. The line weighs little and stretches little, and so stores little energy. If it should break there is no potential for damage from the parted rope.
3. Easy to handle. Does not require gloves to handle, no sharp or jagged hooks as with cable. It does get hot on the hands when you are guiding it onto the spool, and gloves are nice to have, though not essential.
4. No rust. Steel cable rusts over time, the more use, the faster the rust, and it can rust between the strands, where you can't see it.
5. With some study and practice, it is more readily field repaired than steel.
6. No kinking.
Disadvantages:
1. Prone to abrasion. But stronger than steel, so it can take some wear.
2. Often can't get as much on a drum as steel.
3. Cost.
4. Subject to heat damage, not an issue for everyday use or for those who have winches with exterior brakes, but an issue for those who power out under a load (like when descending a too steep face) with winches that have their brakes in the center of the drum.
JPK