How long does it take to beat this game?

[Michael-5]

lestatdark said:

I've set a new minimum for Parasite Eve. My current run through the game took me 7 hours (well 6 hours and 53 minutes) being the first run through the game and not EX mode.

Also my average times for Pokemon White (main story) = 45 hours and Pokemon Black = 32 hours, but White will have a much longer maximum time, given that i'm currently on the 170 hour mark, going for full pokedex completion.

Why does White have a longer completion time? Aren't they the exact same game with different legendaries?

I ask as a long time Pokemon fan, and owner of Pokemon Black.