Not very accurate for me. Wrong by about 400km. (that's basically from one end of my country to the other end)
I find it strange that depending on the device, that I will be detected in different areas (even within the same service).
For example: Google Maps says I'm at a park about a 10 minute drive from my current location. But if I view the mobile version of it on my iPod, it can find me to the room of the building I am in.
Anything that's not google or apple puts me in Hamanako, which is a 2 hour drive on the expressway.