I am another fan of SkyDemon. Apart from the advantages mentioned by other contributors, one big plus for me was being able to use it with my HTC HD2 Windows Smartphone, without having to buy a specific GPS device. Planning is done on my PC, then I just Sync to my phone, and take it into the cockpit. I print out the plog from my PC, and use the phone for a moving map display. The windscreen mount I bought from E-Bay to attach the phone to the window must have cost me all of £5. This was another plus, as I could use it in any hired aircraft, before I bought a share.