In my opinion Google navigate is the best product Google have ever brought out. It uses Google maps technology coupled with voice search and as opposed to having to follow the map directions it talks you through the journey.
When testing this today it works exactly as described. You say where you want to go. It looks up directions and asks you to confirm. On the approach to every turn it told me what was going to happen. Then on the turn explained where I should be heading. At the end of the journey i was told I have reached my destination and it showed a street view image of the front door of the address I had specified.
Sat-nav companies should be very afraid.