Not sure I've seen any. My wife has one and my son has one. The big thing I notice (which I guess is a part of the latest android updates) that is different at least from my phone is no save app to sd card. Not sure if that answers your question. As far as an update I haven't noticed anything different.
I have the 10.1" model and can't say I was aware of any real changes as a user. It's supposed to be faster and have smoother interfaces. The complaints I read about on the 7" model update was the icon for a screen print went away from the front screen.