It's quite a drag as you journey up the bionis especially if you do every optional thing along the way.
But it gets EPIC and picks up HARD towards the end.
One of the final scenes after the last boss fight is just amazing. Those who know, it's the scene that starts with "HOW?!!??" :D
It's one of those scenes that makes the hair on your neck stand up, makes you smile while your eyes water, makes you feel both happy and sad that it's over, and captivates the very soul of the JRPG as it has always been since Final Fantasy IV. The dialogue, the clashing symbols and inspirational strings, the camera pans and cuts, OMFG I feel tingly thinking about it.
I have to go watch on Youtube again right now for like the 1000th time.