Yes, it is worth playing both versions.
I recommend playing Black/White 1 first as this will allow you to understand Black/White 2 completely when you come to it however, jumping straight to Black/White 2 would be fine as they don't refer back that much to cause you confusion.
They both have their pros and cons, for example, Black/White 1 may be considered as having a better storyline, as Black/White 2 has better post-game content.
Hope I helped :)