SPOILER WARNING
I actually went to see this about a week ago, but I wanted to re-watch all the other films in the series before actually coming to any conclusions about this newest entry.
The most impressive thing about this film was the character treatment of Anakin Skywalker (played by Hayden Christensen). Of course, anyone who's been following the series knows that, by movie's end, Anakin will have turned to the dark side and become Darth Vader. The real trick was making it interesting, and writer/director George Lucas delivers big time. There's a surprising amount of sympathy of built up for the young Dark Lord that makes his change of direction all the more tragic, yet believable. By the time he changes sides, he's been left confused about what the jedi order actually stands for. He's come to doubt many of his friends and allies in and outside the order. And, most importantly, he's seen visions of his wife dying and is desperate to prevent it from happening, even if that means learning a long-forgotten sith method of resurrecting the dead. The poor guy has always held his family in the highest regard and to first lose his mother in the previous movie and to soon lose his wife is heartrending. He was desperate when he made his choice.
Something else I really enjoyed about Episode 3 (And all the prequels, for that matter), has been the extra background we've gotten on the characters, situations and concepts of the Star Wars universe. The best examples of these have serve to strengthen what we've seen in the original trilogy. From small things, like Threepio's mindwipe, to larger elements, such as Leia's adoptive father, Bail Organa, getting much screen time, Revenge of the Sith helps give this universe more depth and near flawlessly bridges the gap between the prequel trilogy and the original films. Most importantly,we now know not only how important Anakin's family is to him, but also the lengths he will go to cheat death (Both the death of others, and of himself). Vader's ultimate sacrifice for Luke at the end of Return of the Jedi has always been a immensely powerful moment for the character. With what we know now about the character, it's even more climactic.
Staying on the topic of Anakin/Vader, I should mention the actor who portrays him outside of the black armor, Hayden Christensen. Just so you know, I don't count myself among the seeming majority who thought he was terrible in Episode 2. Yes, he was rather stiff, but he had his moments, especially in the scenes where Anakin was pushed to the limits of his temper. Christenson is much the same in this film, so if you hated him in Clones, I doubt this will convince you otherwise. If, like me, you saw some potential in is performance in the former installment, then you'll be glad to know that Christenson gets more scenes that play to his strengths.
As far as the other actors,Ewan McGregor (Obi-Wan Kenobi), Frank Oz (Yoda) and Samuel L. Jackson (Mace Windu), are at their best. Natalie Portman (Padme Amidala) is wooden, but passable. The real star, however, is Ian McDiarmid as Chancellor Palpatine/Darth Sidious. Early on, before Palpatine is revealed as a Sith Lord, McDiarmid is wonderfully subtle and manipulative in his performance. Once the truth is out, he's delightfully twisted and melodramatic, but it completely works. Brilliantly over-the-top.
This being Star Wars, the special effects are, of course, a large part of the experience. As always, Lucas has pushed the limits of what the current technology can do and gets some very complex and dazzling visuals out of it. From a multi-dimensional battle in the orbit of Coruscant to the climactic showdown between Anakin and Obi-Wan on a wild lava planet, the effects are marvelous. The best the series has to offer. And that's saying a lot.
The soundtrack, by the always excellent John Williams, is, of course, amazing. From the familiar Star Wars theme and Imperial March to the newer compositions, Williams' score fits and augments every scene perfectly.
Unfortunately, no movie is perfect. Revenge of the Sith is no exception. The dialogue, for the most part, is without personality. It communicates what it needs to, but does little else. Also, quite possibly the worst scene of any of the Star Wars films is contained in Episode 3. It involves the first appearance of Vader in his trademark armor. The armor looks as great as always but everything else about the scene is embarrassing, from James Earl Jones' lackluster performance as Vader's voice, to the visual of a lumbering Vader ripping himself out of confinement all B-movie style. Vader fans, you've been warned.
So, the Star Wars series of films has come to end. Despite imperfections, it's gone out on a high note.