Waze is superior in so many ways. It knows (most) contruction sites/road closures (there are many where I live), Waze tells me about speed traps and accidents. Maybe not the best UI, but I definitely get the best results. And I enjoy submitting Road closures etc myself - hoping that I am helping others get where they want faster/without unexpected issues. It's not perfect, but it has definitely saved me a lot of time.
But it's subject to flights of fancy similar to MapQuest circa 2002 where you find yourself taking some strange back road to save little or no travel time.
With no traffic, it's spot on. I feel like it doesn't account for traffic that develops during the commute. Given the length of my travel, the roads may be clear when I start, but very congested before I finish.