It's just a quite good game.
The game mechanic is a classic 3rd person shooter one but:
-the graphic is great (and Japanese level detailed)
-the gameplay always keeps the right pace and rarely (if ever) gets you bored
-the plot is definitely not too banal, especially by nowadays standards
The only cons are the in-game dialogues in battle, battles during which your fellow soldiers will keep shouting the same lines a bit too often.
Definitely a good buy if you appreciate the graphic side of a game. if you have a week spot for Japanese style and if you are looking for a good shoot-em up to relax for a few hours.