This has definitely been my favorite Kurosawa film thus far. There really isn't much of a plot, but a strong plot is not necessary to make this movie good because what it lacks in plot, it makes up for in character. I feel that in terms of characters, this film has the most interesting cast out of all the movies I've seen. Each of the seven samurai have their own unique personality and make a very valuable contribution to the color of group as a whole. We have our wise veteran in the form of Kambei Shimada, the cheerful character is Heihachi Hayashida the "wood chopper," the cold-blooded swordsman Kyūzō, the naive aspiring youth Katsushirō Okamoto, and the comical "blue-collar" samurai imposter Kikuchiyo. The other two samurai Gorōbei Katayama and Shichirōj are less memorable characters, but are still important because of their battle experience. The way these characters interact with each other in the film is what makes it makes it so great. There's not a whole lot of character development in this film, but Kikuchiyo has some decent development throughout along with Katsushirō, and one of the peasants, Rikichi.
Considering this movie was 4 hours long, there are more things I could say about this movie, but I don't want to spoil anything, and if this blog is much longer, I'm not sure if anyone would even read it. You missed a good movie at signs and wonders if you didn't see this, and you should check it out if get the chance (and have 4 hours to kill).