It's worth read up on it in the Pocket GPS World forum as people are still having problems. Biggest issue for me is there is quite a high current drain even when the thing is supposedly switch off (35ma). Before the Li-pol battery came out the manual told you to remove the batteries when you weren't using it. If you didn't they were flat in a couple of days. Same problem seems to exist with the Li-pol battery but it takes longer.
I've had a play with one and its great to see a 'real' map especially if you can afford the explorer 1:25000 series maps.