Here's an example: recently I wanted to get a route around a traffic jam. So, I tried to tell Google Now (on my Nexus 4) to "navigate to work". All of a sudden they took this feature away -- the only thing that comes up is a Google search trying to answer why this doesn't work. And nothing conclusive -- some people are having issues, others not. Android / Nexus was pretty good, but they keep on fixing it further till it's getting more and more broken.