First of all, this is not a re-make of the Seven Samurai and certainly deviates from the original material more than the Magnificent Seven. Think of it as a re-visioning with a sci-fi twist - though you can relax and put all thoughts of Battle Beyond the Stars aside! I should note that while it is not essential for you to have seen the Seven Samurai, you will enjoy this anime all the more for having done so.
It was suprising to see just how much of the original film was presented here - the characters and much of the pacing were much the same - and of course, you'll know who will live and who won't. Unlike Battle Beyond the Stars, this series retains much of the culture of feudal Japan, placing it within a society that has some impressive technology available to the ruling classes and military. Thanks to the design work, this juxtaposition works better than perhaps it should and as you settle into the show, it can almost seem natural.
The original story could have been re-told by this series in 13 episodes - and to an extent it is. However, the greatest deviation from the original is the addition of a new layer of plot beyond the bandits while never losing sight of the villagers and their plight. The new story fits well into the 26 episodes without padding or rushing. This is some of the best story telling that I've seen in anime and is worth the purchase for this alone.
This leaves the quality of the animation. As we've come to expect from Studio Gonzo, it never falls short of excellence! The use of CG is also judicious and fits comfortably with the beautiful cell work. The two great battle sequences are nothing short of spectacular and contribute to a very satisfying climax to the series.
This is not an all out action mech/combat series. This is story telling that is well plotted and character driven, raising it well above most anime fare. If you are looking to try some anime, this is a great introduction.