XII will absorb you of much of your time, because of the battle system, and it's many intricacies, trying to farm treasure chests for rare accessories was incredibly annoying, but then that's only if your doing every single side quest in the game.

Difficulty? Well, it's not exactly extremely difficult, I would say it's average. If you played it through as a standard playthrough, you should be fine. I think the reason why there's so many challenges in this game (No license board for example) is to just make it harder.