I think you may mean iOS 9.3 Beta as you mention the new Night Shift feature which was introduced in iOS 9.3. I have an iPod touch 6th Generation 32GB Gold running iOS 9.3 Beta 1.1 which I upgraded from iOS 9.2 and the upgrade process was extremely easy with the new
Configuration Profile which allows an over-the-air install of the beta. I have had it installed for just over a week and performance and battery have remained untouched. Overall I would recommend this beta however if this is your primary device I would probably wait for a later beta to install just to make sure any of the major bugs are removed.