I can second Andy's negative experiance, especially the TTFF (Time to First
Fix). Imagine waiting 15 minutes to get the satellites. During that time you
think that something is wrong with the settings/Ipaq etc. and if you play
around with them you even have to wait longer.

I was using it with WinPilot when I am flying in glider with no GPS equiped.
Navman is so slow that often the information from WinPilot is just plain
wrong.

Also the connection with the suction cup is a joke. I had to manually adjust
the plastik with tape that a proper connection was made. The suction cup by
itself is also not good because it often happens during the flight that it
gives up.

All in all I would not recommend it!! Look out for alternatives like the
already mentioned ones.

Christian