Hey the GPS is also weather dependent. I have been using GPS from N82 around New Zealand with Garmin XT Mobile software. On a very cloudy day satellite signals may not reach the receiver.

Garmin XT Mobile is a very good software, just make sure you download the latest maps. I found it accurate 99% of the time.

Search for Garmin XT Mobile online. The software should be around 10MB. Then download your regional maps. Whole of Europe takes up to 2GB for the 2007 edition. New Zealand map used only 100MB.