gps unit for nikon D3

Hi all
I am looking for a gps unit for a D3
The best I have found so far is this one: GEOPIC II
Does anyone have any experience of this, or know of others that are worth looking at instead of this one
thanks
I am looking for a gps unit for a D3
The best I have found so far is this one: GEOPIC II
Does anyone have any experience of this, or know of others that are worth looking at instead of this one
thanks