GPS Experience with the HX9V/HX100V
I do not think GPS (features and the way they work) is different between HX9V and 100V.
But there is a big difference between HX5V and HX9V.
HX5V - last position fix is always available when new position is not acquired, whether you turn off camera or not. So if your last acquired position is in New York and you take a picture as soon as you turn the camera on in Chicago, the tagged postion will be New York. Many people do not know this so complain and may be that was the reason this feature is disabled in the new models. But this can be overcome by turning GPS off and then on and allow time to acquire new position. At least the option is there for the user.
That feature was the reason I chose HX5V over other competitors.
HX9V - no GPS position when you enter into an area (like inside a building) with no GPS signal.
I wish Sony will put back the last position fix on new firmware as it is very usefyl.