My dad has the wireless fence. It works well for your dogs, but not for others. A big dog can come into your yard and your babies can't run away. Also the collars they wear, the batteries can go dead in them without you knowing and your babies can get out and then be ran over by a car. Happened to my dad.
He still just has the wireless fence, but has put a wire all around the edge of his yard with electricity hooked to it. So other animals can't come in and if the doggies do make it past the wireless fence, they won't make it past the electric fence. But he lives out sorda in the country and can have a wire "fence" like that. If you live in the city they may not allow it. You may just be better of to get a normal fence.