JTD121: No offense but Android = Google, and for their Nexus line, those are updated as Google releases new versions of Android.
B&N and Amazon (among others) forked Android for their own little ecosystems, but are not proprietary in the same sense that Apples' OSX and Microsofts' Windows are.
Lou: Google financially backed and later bought Android Inc. but the OS is open source and as such is not tied to the more expensive Nexus line of Google Tablets. The versions used by B&N (Nook) and Amazon (Kindle) are highly proprietary.
Indeed, I know. However, the core OS (Android) is open source. The parts they use to lock you into their ecosystem are not. Hence like I said, not 'as proprietary' as OSX/WIndows, which are
completely closed-source and proprietary.
Also, I referred the OP to the Nexus line of tablets because they are running stock Android, are pretty cheap for their specs and capabilities, and will get updates as soon as they come out (if that's a thing you are looking for). I am not really sure what you got out of my recommendation of the Nexus tablets, but I have already argued my point with the Android OS vs Amazon/B&N's Android.