Let’s start with usability! First of all, the Lumia is the winner in this point. It has a fast, easy and smooth interface. The Symbian’s interface is a bit more complicated and laggy, also some elements in the deeper settings are not car friendly with its small buttons and elements. I don’t know if it’s because the smaller screen, but the navigation screen’s map is somehow smaller than on the lumia…
Nokia Drive for Lumia
But I also have to admit, some elements are more accessible on Symbian, for example “drive home”. While on the Lumia you have to go to options -> destination -> favorites, your home address is available as one of the direct points on the start screen in Symbian’s app. A plus for Windows Phone is the possibility to pin destinations to the start screen, which Symbian doesn’t support. This allows you a quick navigation to your most important places and is very innovative! I think every Navigation should have this option.
Nokia Drive for Symbian