I've had this for a while through the beta, and I haven't really been able to adjust to the new UI, to be honest. I haven't found a meaningful use of the channels list on the Home page, opening apps is still what I need to do 90% of the time, and this UI just makes that more fiddly with only a small number of favorites allowed. The multi-tasking via long press home has been removed, making switching between apps also a chore. The side panels with vertical scrolling lists with tiny text are just a backward step, IMHO.

I miss the background images on Home, the changing background colors just get annoying after a while, and with Watch Next not working at all I wonder what's been gained. Oh - notifications are now supported, and they work quite well.

I didn't think I'd say it, but the most recent Fire TV stick UI is slicker, faster, more functional and exposes the content you want quicker and more intuitively than than this one. I'd only been keeping it around for Amazon Video, but I've been using it a lot more recently since it's just a more polished experience. Amazon have really sweated the details with it, but I just don't know where Google is going with their design anymore ... it all just seems half-baked.