It's an absolutely amazing movie, one of the best in the entire Star Wars franchise. It is basically Darth Vader's origin story and rise—I won't spoil it. I have watched this many times as a kid, and loved it. The battle between Anakin and Obi Wan, Order 66, the music, the plot and tragic fall of the Republic, and fall of the hero Anakin Skywalker... It's like a puzzle piece that was placed to fill in the originals, and reveal the truth behind the Empire, Palpatine, and of course Darth Vader's tragic story. I definitely recommend it, and would give it a lot more
Ps. Don't listen to the grumps scolding it—they are just disappointed that this isn't the EXACT SAME thing as A New Hope.