I recommend you buy it. There are 3 main story paths and each one has a unique story. Youll find that based on that premise it will be worth your money.
I'm not a fan of tactical RPGs so I can't say whether it's good in that regard (though many people have praised it from what I've seen). I'm playing for the characters/story, and if that's important to you, I'd totally recommend it. All of the story paths are great and the characters are all wonderful and likeable.