13 Assassins certainly recalls Akira Kurosawa's classic The Seven Samurai with the assembling of a small team against a larger enemy, the late addition of a final "samurai" who is not actually trained and certified, and a humongous battle scene climax (@45 minutes to end this pic) that leaves the jaw dangling from your mouth and delivers major satisfaction.
The main difference of note is the cruelty of the villain, which crosses the line into the horrific, making this one not for kids. Director Miike is known for his "pulpy" style, and while I don't think I've seen more than maybe one of his reported 80 films, I can say that this one is pretty much classically/artfully shot, making it a pleasure to watch.
If you can get the big screen experience, go for it, but 13 Assassins is also available on Pay-Per-View. If you like action, honor and swordplay, not to be missed.