Braided polyester rope is more abrasion resistant and stretches less than comparable nylon lines.
It holds up better than nylon when exposed to sunlight, and is almost as strong. And it has better dielectric properties (is less likely to conduct current) than nylon.
On the other hand, it does not absorb shock loads as well as nylon and its dielectric properties are not as good as those of polypropylene.
12 strand diamond braid and double braided polyester are used by tree care, roofing, window washing, and rigging contractors as vertical lifelines in fall protection systems, and by tower builders as guy lines.
Work at height contractors use double braid polyester as bull rope, climbing rope, and positioning lanyards. And they use it with a steel cable in the core in flip lines (the steel core style is not used when working near power lines)