What kind of dogs do you have and how old are they? This may help determine your best fencing.
I have an underground invisible fence and have had it over ten years with various breeds and love it. However, it is best to start them out on it as pups. It is not impossible to train an older dog, just easier to teach boundries to puppies. The key is training either way. You can't just put it in and let them loose and expect them to figure it out.
They also make a "radius" invisible fence, one you don't have to bury but the transmitter must be in the center of the fenced area and will transmit a signal in a specified radius around the transmitter.
If you are going to leave them outside unattended for any length of time, a physical fence would be a better bet and would keep people and other animals out as well as keep your dogs in.
I don't use my invisible fence when I am not at home to contain my dogs. They are still vulnerable to intruders, theft, etc. They may stay in but you need to be able to keep people/critters out as well.