1 - maps are something other than the navigation software!
2 - iGO also uses the same maps as Garmin, Navteq maps thus
3 - for iGO advantage is that use other maps from other providers (TeleAtlas (TomTom), local provider, etc.), Garmin rarely
4 - travels frequently throughout the EU, and using at least two navigation (with iGO and Garmin and Sygic) iGOMyWay (iGOprimo) is the best in the calculation and the best guides and displays in the cockpit and all alerts the driver. This often makes even the Garmin, but not for the US / EU units.
5 - China are really rubbish, iGOprimo works, but weaker, use prefer iGO8 or Amigo, those needs less hardware demands.