The tree service I work for tends to just use older climbing rope to tie trunks together when there is a weakness and it looks like one might eventually split off. Is there a significant advantage to using a cobra cable? Is it stronger?
UV protected is probably the biggest advantage.
It is easier to splice.
It has more stretch.
Black hides better in the tree.
Depending on which climbing rope you are using (and how worn it is...) and which Cobra rope you are using, it may or may not be stronger.
For what its worth, I like the Branch Saver rope at TreeStuff.