I have one of the burried types, no idea which one. The system is not in place to stop your dog, its a training tool. I used a shock collar (beep, vibrate, shock options) to train my dog from early on to walk off leash so this was an easy lesson. If you train your dog correctly with this, they won't get close to the line and won't have to worry about him/her running through it. I have a 60lbs german shepard and she has never crossed the line. Our company came out, installed and then spent an hour or so with each dog doing basic training.
I (my wife) has a pomeranian and her hair is too thick to make contact, and given she is around 4lbs, we don't want to turn it up. I'm sure we could figure it out if we wanted to, but a dog that small hasn't been any issues.
My uncle has 2 labs w/ a wireless radius fence in the country and it works well for them as well.
All in all, I would 100% reccomend. Just know that there will be some training that you will need to do to get the most out of it.