While I don't think these films are quite up to the level of the other great Japanese samurai films of the 1950s (such as Sansho the Bailiff & Seven Samurai), the really great things about the Samurai Trilogy for me were in the marvelous use of natural surroundings, the attractive Japanese leading ladies, and above all being able to see Toshiro Mifune starring in color.
Regarding the DVD transfer, let me first say that I am a frugal guy who does not think that any DVD, however good the transfer, is ever worth 30 bucks. That said, I don't know what all the fuss is about over the image quality on these disks. The film was not released in widescreen so the full-screen image is correct. The only scenes which are perhaps too dark are in the end of the second film, because it was filmed that way originally! The VHS is even darker as far as I could tell. I have 20/40 vision, yet I had absolutely no problem reading the subtitles ever in any of the three films. The image quality in general is not Jeanne d'Arc but it certainly never came close to impairing my ability to enjoy the films. Finally, there are no special features beyond theatrical trailers on any of the DVDs, but the three-pack is also priced cheaper than any other Criterion issues (less than $20/disc) so why complain!