The game is not worth it if you don't speak Japanese as you will not be able to understand the story and how the characters are connected to each other. This is my opinion as I have the game and I don't speak or read Japanese.
What is nice about the game though is the soundtrack, presentation and the parallel storyline/gameplay as you are playing through the eyes of 5 protagonists whose actions intertwine with each other.
I bought the game because a) it looked interesting, b) live action (mostly still pictures though...I wonder when I'll start to see more cutscenes) and c) unlock the Type-Moon scenario.
If you do want to try and play it...I'd wait until the price comes down (or find it for real cheap) or a Greatest Hits version is released.