Anyone using the D300 with a GPS?

[cincyimages]

If so I would love to hear what GPS devices people are using and do they work as advertised?

Here are a couple of photos of one device but it costs much more than I am willing to spend:

http://www.dawntech.hk/di-GPS/img/DSC_0802.jpg

http://www.dawntech.hk/di-GPS/img/DSC_0818a.jpg

http://www.dawntech.hk/di-GPS/n2.htm

[K1W1]

I can't actually see a need for it except in specialist type applications. I can understand if you are commissioned to take infrastructure or architecture shots but anything else seems to me to be technology for the sake of technology.