Just ordered a reference rx480, to be honest after checking all the reviews its not much different when it comes to overclocking, the reference cards when overclocked are sometimes faster than the AIB cards, only down side is the higher temperature and noise levels which I will have to live with.
Not really, the reference card is a 6 pin only. SO if you are about to use max performance of your card or ethereum mine with it, the 6 pin is not enough and it will take power from motherboard and pcie express and might burn you pcie or your motherboard.