I have used most of navigation software packages from different vendors (Garmin, TomTom, Sygic, NDrive, CoPilot) but seems that best one is still iGO Primo 2.4 (from functional point of view). But it has (at least for me) one very big drawback: usability and UI design. It looks mostly either like crap or its usability is suffering big time, usually texts are too small and either there is problem with text size contrasts or color ...