The storyline is awesome, but if you want a storyline similar to other FFs you will be sad. It's about 90% grinding and 10% story. You will have to spend an absurd amount of time leveling to touch much of the story. It is likely that you will go for weeks or even months at a time between plot points which makes the continuity of it a little hard to follow.

The Chains of Promathia storyline is one of the best, but only a handful of people on this forum have even made it through, which is something to say considering how long they've been playing. It is difficult on so many levels to make storyline progress.

If you want a story wrapped up all neatly that you can easily follow along (like most FFs) then this is not the game for you. This is mostly a grinding MMO with the benefit of a very deep story.