Read the manga. Yes. By God, do it.
Though from what I've read, heard and seen, this game is really disappointing. Some of the cooler arcs were cut off, Juda and Shuh aren't playable, you don't fight Souther on the steps of the pyramid and overall, the game is just a slower, more boring version of Dynasty Warriors. The soundtrack isn't even good, either. Just your generic cheesy hard rock stuff. Though I do admit, the trailers make it look really impressive.
I'm going to wait until the second iteration of this comes out, if it ever does. Hopefully they will set things straight with that.