When I've watched DVDs of Sergio Leone's "Spaghetti Westerns", such as A Fistful of Dollars and The Good, the Bad, and the Ugly, I've had the option to choose soundtracks in either English or Italian. Both soundtracks seem to have been recorded by the original cast, and it isn't clear whether one or the other matches the actors' lips.
Which language is preferred for these films?
Did Leone consider one of the soundtracks to be the "official" dialogue and the other merely a translation? Did he supervise one of the recordings more closely? Have critics expressed a preference?
I don't speak Italian, but I'd rather hear the Italian dialogue with subtitles if it's closer to the director's intent.