I've noticed a marked dip in performance on the campaign map since opting into the beta...
Battle performance remains the same.
HappyCompy's Rome 2 video emporiumCompleted Campaigns:
ETW: Italian States, Mughal Empire
Shogun 2: Uesegi, Date, Shoni
Rome II: Rome, Venetii, Bastarnians, Pontus, Athens
Attila: Franks (minor), Vandals (cultural)