Exactly, Chlosmum. The fences need to be higher. Pitties and other breeds that are athletic can scale those fences. My boy is over 5 feet on his back legs, but he's weighed down like a ton of bricks and could never scale a fence. But even still, if we had a fence, he'd greet passersby with a huge HI, with his feet hanging over the fence and cause heart attacks. I'd get no less than a 6 foot fence. And electric fences? Do those even work? Besides the questionable shock they deliver, I'd never trust an invisible fence with a determined dog.

Your smart not to trust them. If a dog is HA/DA/SA trust me they will take the pain to go threw it.
You have to train them with it, it is not a put in and fixes all. Bully breeds, Mastiff breeds and Labs have very high pain level, and have to be trained from pup to adult with them, for them to be effective.