I will wait six months before I upgrade. As I said earlier, let others find the bugs and give the developers time to finish their bug version of whack a mole.
I am a developer and can guarantee bugs have crept into the version upgrade. There is 0% chance that 16.04 is bug free. I would bet my life on it with utter confidence for a dollar. How severe they are, who knows. 14.04 for me for 6 months.