My father have geothermal when the house was built. There's pro and con to it. The pro is that of course it save electricity since you can use it for hot water tank, heat the swimming pool and for AC/Heat. It's environmental friendly (no carbon release and such).
The con part is depending on the size of the house, you will need large landscape to put all the pipes underground. Also, when hot and dry summer hit for long period of time, the temperature under ground will increase a little, can significantly impact the temperature to cool the house. Also, if geo heat pump break, you will not able to get any hot water (after the water tank recirculate with cold water). And last can't drive any heavy equipment over the yard where all the geo pipes located, like big Utility truck, or drilling rig or whatever. Due to ground shifting and can crack the pipes underground.
Oh, forgot one more thing to add, talking about "saving electricity", actually it cost nothing for him, no electric bill, he usually get about $4000 every year from BGE (Baltimore Gas and Electric). You know how he did it?