LogFAQs > #961333884

Whichever one you want to play first.

Vesperia is very slow with characters learning abilities and moves, especially in the beginning. The game also has sidequests where you need to backtrack with no prior notice that are missable.

Berseria has the more modern QoL adjustments but lacks world map traveling and also does away with tp. It's faster paced to the point some say it's just button mashy. The main character does break the battle system in half once you understand her ability. So difficultly might be easier.