Comparing to the external charger of YOUR iPhone, which requires you to pre-charge the charger, and then plug the charger into your iPhone for actual charging. When you're on the move, YOUR iPhone chargers took TWICE as much time to charge a single freaking battery inside YOUR iPhone. And your external charger is cumbersome; a spare battery is light. Good point! What if your USB port of YOUR iPhone finally died? Can you swap your battery? You could continue to use N900 without USB for three months, all you can do with YOUR iPhone in the same situation is to send it back for repair. If you've problem with the warranty, talk to Nokia, not here, provided that you actually OWNED a N900.