Yup. If you encounter heavy traffic on your commute and there are alternate routes, Waze is an excellent source. It will route you off the highway pretty easily to a faster route. Google Maps on the other hand requires the road to be practically shut down before it tells you to get on surface streets.
A big difference between Waze and GM is the map data. Waze is crowd-sourced; anyone can edit the map. This can be good and bad. One good thing is Waze is aware of intersections that have time-restricted turns. And, when the map is wrong you can notify the community and it will get fixed (or you can fix it yourself). So far I've had no accuracy issues with Waze. I've been using it for over 2 years daily for commuting and pretty much anything else. The realtime data (traffic, hazards, police, etc.) cannot be beat. Of course, this is all useless if there aren't many Waze users in your area.
You can edit the Google Map data as well. I complained once that Google Maps was not picking up that I was getting in an exit lane and was assuming I overshot the exit, and some Google Maps community guy went ahead and fixed that info.
But yeah I've had no problems with map accuracy in the Bay Area. I think many people use it here which ends up making it a pretty decent product.
I do agree the app is spammy though. The interface is crowded, and I've seen ads cover up my ETA or next step even. That's pretty dangerous. Also I bet a lot of people drive and use their phone for Waze points. How many people actually have their passengers as opposed to drivers actively using Waze anyway? Not that many I'd bet.
I did a heads up comparison back in Dec 2013 between the two products and Waze routed me on a 26 minute route to the airport from work whereas Google Maps had me sit in traffic for 44 minutes. I took the Waze route, and I got a little unlucky with the lights. The actual transit time was something around ~ 30 minutes. Still better than GMaps.