This article is taking the estimated arrival time into account, but not sudden external influences like accidents or traffic jams. I’ve used Waze in São Paulo, throughout the UK and Germany, and find it to be very creative concerning route finding. In the same situations, Google Or Apple maps seem much more conservative and consider “riding out” the traffic jams instead of taking nifty shortcuts. Especially in São Paulo, that was a HUGE time saver.
Another feature I prefer with Waze is integrated speed limit display. I never had to endure any ads though in Waze, that’d be a reason to quit and switch.