I bought it for a friend, this is what he said:
He texted this to me:
This game is a lot of fun and I can't stop playing it, but every time it comes to a cutscene or story part, I don't understand what they are saying. Just because I don't understand the game, it is not stopping me from playing it or getting farther in it. When I finish playing the game, I should let you borrow it if you have some time to play.
From what he says, it is definitely worth the playthrough, even if you have never played a Yakuza game before, it is well enough designed that almost anyone can play without having a language problem unless you are interested in what they are actually saying. I read through the back of the box and it does seem like a really good game that I may want to try out some day.