I run AnywhereMap and like it -- but I had the PDA and bluetooth GPS already and did not see a reason to buy yet another battery powered device for the sole purpose of having a backup GPS system. The latest version of Anywhere map seems to be fairly free of bugs and the latest models of iPAQ are fairly easy to read in sunlight. Unless you are using a connection to the aircraft's power, battery life may be an issue. I get 8-10 hours of operation per charge, the problem is that, like aircraft fuel guages, the power meter on the PDA is accurate only when it says empty and there is no way to check the charge state of the bluetooth GPS.
For my purposes, it was a better choice to buy software that allows my general purpose device perform an additional function rather than buy a dedicated device that performs a single function.
Bruce
