There's nothing wrong with owning a Nook, though if you've outgrown the custom OS and want to transform it into a standard Android tablet, you have options, one of them being a Nook-to-Android (N2A) card. Even better, the N2A team just updated its software to Android 4.4 KitKat, which is the latest version of Google's open source mobile operating system currently available.
N2A works with the Nook Color, Nook Tablet, Nook HD, and Nook HD+. Pricing runs $30 for an 8GB N2A SD card (2GB app space, 4GB storage space), $40 for a 16GB card (5GB app space, 9GB storage space), and $50 for a 32GB card (5GB app space, 25GB storage space).
Alternately you can use your own SD card (must be SanDisk Class 4) and download the software for $20. Once you have a properly formatted card, simply pop it into your Nook device and boot into a stock Android KitKat environment.
If you already own an N2A card, you can snag the KitKat update by navigating to the App Corner app preinstalled on your card. Once there, tap the KitKat Upgrade logo and select the image of the Nook. The upgrade app will automatically start downloading to your device.