My dog attacks horses. Difficult situation considering we live on 10 acres and the horses are on the property! The radio fence is the best thing I ever did. We got the stubborn dog one from Petsafe. I have it set on a level 2. Level 1 is just a beep, which she learned to run through, so I set it to level 2 which is a mild shock and stops her every time.
Initially I did set it to a level 4 which is a pretty strong shock, so she learned very quickly that crossing the boundary meant pain. I don't have to have the collar on her full time but the neighbours have a pitbull visiting at the moment and he comes over... I don't want to risk him leading her away because as I said she is a hunter and her and a pitbull in a pack together would be a recipe for disaster. I love pitbulls and this one is such a sweet fellow, but they DO have the attack instinct, and a fighting dog and a hunting dog together in a pack will do damage.
She also used to be a runner, real bad. You opened the door, she was gone. Moving to the acres mostly fixed the problem but she still wandered. Getting the dog fence has totally stopped the wandering, and as long as the horses aren't in the house paddock, it has also stopped the chasing and attacking.
I wouldn't recommend the dog fence for a long haired dog, because the contact points on the collar can't reach the skin through thick fur, so you would have to totally shave the neck because the collar DOES turn (half the time my dog has her collar half way up the side of her neck, and I always put it on straight). If you don't mind a long haired dog with a shaved neck, then go for it.
I only use the one collar that came with the fence but I've been thinking about getting a bark collar for my BC cross because she has that awful high-pitched yip that so many working-bred borders have.