Navigation on a mobile phone is always going to be kind of second rate compared to a stand alone GPS unit. Screen size is a factor but the big thing for me is the sound. Phones just don't have large enough speakers to overcome car noise and there's no way you will hear it over the stereo. If you can plug your phone into your stereo it would take care of that problem.
Waze has some good points and bad points that I'll touch on here. This isn't a full review of Waze but I will tell you first is it's FREE so give it a try.
Waze is very much the entire GPS navigation package. It is very acurate and performs just as it should. You can also add yourself as a user, what this does is adds a social asspect to navigation. You can post about a traffic accident, police activity, or just say Hi. Waze will tell you how fast other users are going and collect other data that will help you on your trip. They add in some game like things as well. The view becomes dark at night and light during the day. A nice feature I noticed is that during a phone call Waze will still tell you the direction you need to know and the other party on the call can't hear it. Entering an address could be better, it does intigrate with your contact list but you have to blind search, no list view.
Waze is happy to tell you all about thier service see the video below.








