I've got the 48" from Premier. I have not lost a chicken to any predator since I started using it around Christmas. I only lost two to foxes in three years before I got it, so I can't say it is absolutely without a doubt effective against them, but I think it will be. I mainly got it because people like to drop off dogs out here in the country.
Foxes can climb many fences. Someone on this forum had a video showing one climbing a chain link fence. If your run is small enough, you can cover it and make it predator proof. But it is really hard and really expensive to make a large run truly predator-proof.
I have a 12' x 32' run that is pretty predator-resistent but I don't consider it predator-proof. Part of it is covered but not all and they can still come in over the top of the coop. But on the fence on the open part, I ran fence up about 2 feet above the posts. It is just standing there under its own stiffness. The theory is that if something like a fox or raccoon tries to climb it, the fence will bend back over them over under their weight and they won't be able to climb in. I really raised it to stop them flying out, but used this method since I was raising it anyway.
The biggest problem I have with the electric netting is that I have to regularly take it down to mow around the boundary. The grass and weeds will ground it out when they are wet. How often you have to do this of course depends on your climate and how fast the grass and weeds grow.
I think the chicken's feathers pretty well protect them against getting shocked but if their comb touches it when it pulses, they do get hit. I'd hoped that they would keep that stuff eaten down so I would not have to move it so often, but most seem to learn to not get too close to it. I have seen the rooster get hit a few times, so maybe they have to occasionally relearn that lesson.