I use Waze for the camera warnings, but have noted a bunch of times it was not giving the best directions. Just yesterday, I missed a step by mistake causing me to use a different route and the ETA moved 8 minutes later, but then very quickly went back to the original ETA. Then I got stuck in traffic, as predicted, and on a whim took a side street instead of staying in the traffic, and my ETA moved 5 minutes earlier (and then dropped by another couple of minutes as I was going).