I don't like it at all. It has a cartoonish interface and eats my battery alive. I don't need real-time traffic information while I'm driving, I get that by looking out the windshield.
Granted, I'm sure that interface can evolve, but the fact of the matter is that Waze's technology is not defensible.
Waze can tell you if there's an accident along your route, and point out where it is, and it is pretty accurate most of the time. That feature alone has saved me countless hours. As far as battery usage goes, it's no worse than Google Maps.
I'm not a huge fan of the interface, or the gamification aspect, but the data is just that good.
Isn't that information dependent on the number of users in a given area? So if very few people in a metropolitan area use Waze, the information would suck?