I was more than pleased with the Masterworks Edition, although I've heard (but not seen) that the Criterion DVD is the best. See exerpt of review below, reverberates the sentiments I've read:
"However, this gem's transition [Ran] to DVD has been cringe-worthy on Region 1. The Fox Lorber edition is noted as being one of the worst transfers in existence, and while many were satisfied with the Masterworks edition, most who were familiar with the film (and many who weren't) recognized that there was an obscene amount of digital manipulation. The result is the film's colors looked utterly artificial and the film has nowhere near the serene look it normally does."