My mother contains her two GSD's with underground invisable fencing. She loves hers. But it takes months and months of training every day. You have to walk the dog near the lines, and teach them not to go out of bounds. Mom's dogs don't even ware there callors anymore, as they already know what happens if the cross the lline. Mom had hers installed by the company, and they did a session on how to train. Also there is a video, and book. It comes with flags to mark out the boundries if you need them. They say "This Dog is contained by Invisable Fencing" also a sticker for your Mailbox that says the same.
Cons to it are, people will not know your dogs are contained. The mailman will have no idea. Other dogs can also still come into your yard. And it's not really something you can leave them unattended with. Sometimes her dogs have run out of bounds so quick, and they were zapped when they tried to cross back in. (Of course she also put them in the truck and drove off forgetting thier callors.) Duh!