Android N, inside my pocket
One thing's for sure: Using Android N on a device you carry all day is a very different experience from using it on a secondary screen. For better and for worse, it gives you a whole different perspective on the state of the software and its real-world user experience.
Let's start with the good, shall we? In this third pre-release incarnation, Android N is (for the most part) impressively smooth and snappy. Most of the time, I don't even think about the fact that I'm using a beta version of a still-in-progress OS update.
Android N feels immediately familiar, which is generally a good thing. Sweeping visual changes should be a rare occurrence with an operating system -- more the exception than the rule -- and Google is absolutely not trying to reinvent the wheel this go-round. If you're used to Marshmallow, you'll feel comfortable from the get-go with N; in fact, I wouldn't be surprised if it took some casual users a fair amount of time to even notice what's different.
The differences are definitely there, though -- and once you clue into them, some of them can actually be pretty significant in day-to-day use. Android N's refined notifications, for instance, have become a real highlight for me and something I miss when I go back to a 6.0-level device. Google has taken a good thing and made it better, with clusters of individual cards now being grouped together by app and easily expandable.