You'll also have an unsecured laptop able to bounce around the cockpit at the first encounter with turbulence. I don't like anything that big and that heavy being loose anywhere near the pilot or the panel.
The software Diggrr linked to also doesn't have any aviation data aside from the cross streets where the airport is located. As I said, if you want something to play with while you're flying the commercial carriers, a map program on a laptop will be fine if the antenna can receive signals from inside the cabin.
But if you are a pilot, the safety risks of an unsecured computer and absence of navaid information makes a ground-based GPS system a dangerous waste of money instead of a bargain.
BHD