Synthetic seems to stay flat on the drum, and doesn't bind up as bad, or kink as bad. It's also lighter weight, won't rust, and a frayed strand isn't likely to slice through your glove. Also I think if you managed to snap the cable, synthetic might be less likely to cause serious injury.

On the other hand, with synthetic I think you had better be careful about running the line over sharp rocks, and it would also pay to be careful about not raising burrs on the rollers (IE use 1/2 a boat roller).

Also, it's a good idea to use a tree strap to keep from kinking the cable (and to prevent injury to the tree). I really like Tusk's winch accessory kit. It's cheaper than the Warn kit, but the case is a little nicer, and it comes with gloves in addition to the ****** block and tree straps. The bag is also big enough that you can fit an extra tow strap in it.

I've seen people damage winches by reversing and jerking the cable tight, or by stacking the cable up...

 

yeah, the synthetic rope doesn't store energy either, so if it snaps it won't whip back like the cable will...