The darker colors (or black) seem more UV resistant. The line seems to last 5 years, so with normal Chesapeake Bay use. if you're in cold climes with a short season, or on a mooring most of the time, then braided will last a lot longer.

If by abrasion, you mean rubbing in chocks, then I like braid better. Larger line, thanks to geometry (pic for circumference and r^2 for cross sectional area) are the biggest protections. If you mean rough docks or piling, then I'm not sure. I certainly would discard a grungy inexpensive line sooner than a more expensive braided line.

I think if you're getting breaks in the braid, you have some very aggressive abrassion or UV has gotten to the line, or it's just time to source som bulk line.

We don't have eyes for the dock lines. That makes it easier to lose some length.