I have had dogs that loved being on a cable and I have had dogs that hated it. The placement of the cable and the personality and breed of your dog are very important.
I had a German shepherd who we once tried to put on a cable. He hated it so much he tore it off the side of the house. We got an electric fence after that, but that did not work either. We ended up putting up a wooden fence, which he was fine with, except the gate had to be short enough for him to see over or he freaked out. His protective personality made a running leash a very bad idea for him.
We had another dog who was a husky/border collie/chow mix. She liked the runner leash. She was relatively strong, but never pulled the runner out. We did not have a fence when we had her and the runner leash was a good idea for her. She was a stubborn dog who loved to run. Our yard was long enough that she was fine with that leash. She also did not mind being on a chain when we were gardening in the front yard. (Which was important because we lived on a busy street at the time). She was not protective at all and would have been happy to sit on a leash outside all night (which we did for her safety when we went camping.
A third dog, and Australian shepherd, has always hated any from of leash. He comes well when called, but wanted to spend more time outside. We were in a different house at the time and chose a chain link fence. He loves being outside in his "pen" so much, that he stays in there even if we accidentally forget to close the gate. He is also a stubborn dog, but he listens to commands.
Those are three different dogs I have owned that are different kinds of herding or hunting breeds.
As to your specific breed.
The Pyrenean Shepherd was designed to be a sheepdog, and as such is full of the same sort of energy that other herding dogs have, but in a surprisingly small package. This adaptive dog wants to, and can, do all the jobs on the field, and is a natural herder. A dog that needs a job, its cleverness makes it ideal for other work and dog sports such as flyball, competitive obedience and agility. This dog is good with children that they were brought up with. They have a sense of protector over the children.
Pyr Sheps are "one-man" dogs, attached and dedicated to their owners, with a desire to follow them around the house to help with daily chores. They sense every mood and often seem to be able to read their masters' minds, as they are constantly watchful. Because of this, they are extremely trainable.
Their natural wariness, while valuable in a herding dog that may need to alert their shepherd of strange animals or people, combined with their herding bossiness, can lead to shyness or aggression in even the most friendly puppy if not properly managed. Frequent socialization from a very young age can help counter this trait.
Your dog, if they conform to breed standards, would be more like my old German Shepard. If they are very loyal to you, they will hate being on a runner and would be much happier with a short fence. The runner would drive your dog crazy because it would not be able to be near you. They are naturally wary, which means that they have the chance of tearing out a runner chain if another dog goes by and your dog fears you are threatened. That is why a Pyrenean shepherd would be happier in a fence.