Firstly I have to say I didn't know this movie is the last in the series, so I watched it as a first one, but I think it maybe doesn't matter, because it shows the story from the very beginning.
The story is quite straightforward I would say, but what makes it very good are all the little nuances, talking about ethics, thinking about different topics like if it's right to kill people for greater good etc. Then a little plot twist near the end and the ending itself makes the movie a tragedy which will move your heart with emotions.
I also liked the flow of the movie, which (even though there are lot of brutal scenes) felt very calm, combining it with the very fitting soundtrack.
The fight scenes were also very well done and quite naturalistic.
I can recommend this for anyone who likes "samurai movies" and to anyone who likes to be moved by emotions, even though they can be sad.