It is fun and has a ton of content. Graphics are fantastic and it is a very enjoyable game overall.
I never played the DLC, so while I was able to piece the story together somewhat coherently, it is just all over the place. I would look try a different Final Fantasy if you want a good story personally (again, cannot speak for Royal Edition). If you do want to try to piece it together, watch the movie and the six episode anime first.
But if you are looking for a large scale world with plenty of action JRPG gameplay, pick it up. It does do well in that department, even though the combat is simple.