I do not think there is as much difference between brands as people want to claim. The cheap ones seem to work about as well as the more expensive ones with the possible exception of the ones that have the metal clip.

the width and thickness does matter, and that varies a lot. Thicker and wider is generally better. nylon is general the best all around material.

I would not worry all that much about UV. It takes a very long time for UV to have much effect on them. I have a bunch I used to put some fencing up almost 8 years ago and they are still fine.

Extreme cold can cause issues with them though, but normally they won't just break due to cold. The cold can cause them to become more brittle and more likely to break when moved around.