>>27911514As other anons have said, the legendaries are swapped between versions.
Other than that, each version has an exclusive city, which are vastly different.
White's city revolves around catching exclusive pokemon. I played black so I'm not very familliar with it.
Black's city revolves around you battling pokemon, allowing you to rack up extra points to get battle items and other things that help make your pokemon stronger.
So what you need to ask yourself is:
Do you prefer Zekrom or Reshiram?
and,
Do you prefer catching them all or battling?
and then base your decision off that.
