There is a sort of controversy in Mexico with pictures being shown in movie theatres dubbed in Spanish or with Spanish subtitles. This Dub vs. Sub debate has been going on for ages, but it has become more evident lately because more and more movies, specially the family-oriented ones, are shown dubbed in Spanish, and sometimes the subtitled version is not made available. A lot of peophe really hate the dubbed versions, they want to hear the real voices in English and prefer to read the subtitles. But also, a lot of people prefer the dubbed versions because, well, they don't know English, or, like in so many other countries, they don't know how (or don't like) to read. Personally, I have no use for either one of them, but only because I know English. So, when I go to the movies, I skip the dubbed versions (because sometimes they are not made properly) and I ignore the subtitles.
Some countries don't have a choice. I don't know if it's entirely true but, I have heard that movie theatres in Spain are required to show all international films dubbed in Spanish ONLY. Or that subtitled versions are not very accessible. I think that's stupid.
My position in this debate is neutral. I don't think that one version is more important than the other one in the context of the Mexican movie-going public. The important thing is that we have a choice. Both versions should always be available to public. Much like the audio options in a DVD.
Which brings me to the Spanish dub in the Revenge of the Sith DVD. Though I prefer the English version, I have made it somewhat of a tradition to watch the Star Wars movies dubbed in Spanish with my Dad, because that's the way he prefers it and because non of the Region 1 Star Wars DVDs have Spanish subtitles. Also, my sister has done some voice over work recently, so I have learned to appreciate the craft and talent of voice actors.
Yesterday, I got together with my family and watched Episode III dubbed in Spanish. Not to be confused with the awful (so I'm told) Spanish dub from Spain, fortunately, this was the same Spanish dub that was released in theatres in Mexico and Latin America, and I have to say, It was not that bad. Some dialog is slightly changed to match the screen actor's lip movement, but, other that, most of the voice acting was convincing. Mario Filio is okay as Obi-Wan Kenobi and Cristina Hernández is great as Padmé Amidala. Jesús Colin nails it as Chancellor Palpatine/Darth Sidious, he sounds almost like Ian McDiarmid. Irwin Daayan is also very good as Anakin Skywalker, although he sounds a bit older for the part.
The cool part about this voice over work is that they paid attention to continuity and used the same cast for Episode I and II, and also the Clone Wars micro-series for Cartoon Network, as you can see here and here. Also, some of the same voice actors worked in the Spanish dub for Episodes IV, V, and VI, so, you can hear Arturo Mercado as Yoda and Carlos del Campo as C-3PO throughout the whole Star Wars Saga.
Now, since they are not shown in the DVD credits, and so that they don't remain as unsung heroes, here is the entire cast list of voice actors for Star Wars Episodio III: La venganza de los Sith:
Anakin Skywalker: Irwin Daayan
Padme: Cristina Hernández
Obi Wan Kenobi: Mario Filio
Canciller Palpatine: Jesús Colin
Yoda: Arturo Mercado
C-3PO: Carlos del Campo
Mace Windu: Víctor Hugo Aguilar
Conde Dooku: José Lavat
Bail Organa: Gerardo Reyero
Darth Vader: Federico Romano
Clones: Miguel Angel Ghigliazza
Nute: Paco Mauri
Ki Adi Mundi: Carlos Aguila
Eeth Koth: José Luis Orozco
Saesee Tiin: Gerardo Vázquez
Kit Fisto: Ismael Castro
Tion Medon: Alberto de la Plata
Odd Ball: Rolando de Castro
Mas Ameda: Mario Arvizu
Droid médico: Humberto Solórzano
Piloto de Fireship: Raúl Anaya
Super battle droids: Oscar Flores
Super battle droid 3: Javier Rivero
Droid de batalla: Igor Cruz
Capitan en Cruiser: Herman López
Capitan Antilles: Andrés García
Genaral Grievous: Eduardo Giaccardi
Droid técnico: Carlos Hernández
Typho: Ricardo Brust
Niño Jedi: Andoni Sánchez
Piloto en Cruiser: José Luis Mora