I recently got the nook 1.2.1 firmware and it locks down the device (again). I knew I was likely to lose all my tablet-y stuff but frankly it wasn’t doing what I wanted it to and at the battery life I might as well have a new tablet. I blame the gapps, which never close and sync in the background nonstop. To add insult to injury, nook apps tend to assume you have colors. No colors makes for a very confusing experience. Also the eInk display tended to be hacky with special secret handshakes to activate fast mode, etc. Turns out someone else got really fed up with it also and decided to write a launcher and android ROM which was based on the official 1.2.1 and also knew someone might actually want to use the nook as a nook! WOW! So the smart guys over at XDA put together NookManager which does all this good stuff and still keeps the B&N official applications so you can read their books for free in the store. It even does the right things with the buttons which is really sweet.
That being said, Amazon seems to know something is up because the kindle app isn’t available in this ROM (although I suspect it’s because it upgrades the android core OS on the device) nor through the store. You have to sideload it from here, which is as simple as using dropbox to grap the APK and then opening it on the device. It does have the google RSS feed cacher, which I have desperately wanted and would crash immediately on the old ROM. The browser is still nothing special and will “forget” to update the page if you throw too much JS at it.
The only real rub is that I have to reseat my SD card for the nook to see it if the Nook completely runs out of battery. A small annoyance since I have 30 microUSB plugs next to my bed but still requires fingernails.