I did upgrade because I failed my saving throw against shiny.
But I am loving it! For books bought on Amazon, there is no real reason to keep them on the Kindle now, other than being out of Whispernet range, since you can directly access those you have purchased and removed from the main screen. For tech stuff that you got from elsewhere, not so much. Haven't tried searching the Amazon held books, yet. Will try that soon and get back to you.