Although the series suffers somewhat from repetitiveness occasioned by the need to keep re-orienting viewers as multiple story sequences are interrupted for long periods of time while first one, then another, thread is begun, I am glad that I was patient enough to view the entire collection. If you like Ken Burns's thorough and somewhat laid-back style, you will find it agreeable here as in his other series, even if this is not quite his best effort. One should bear in mind that this is primarily an historical documentary, not a travelogue or guide to the parks.
In terms of content, I'd probably give the series four stars; but I was disappointed in the video quality of the new motion-picture footage that Burns's photographers accumulated over six years of hard and dedicated work. I believe that a fundamentally wrong decision was made in the choice of medium. Burns has a love of old-style photography, and the many stunning examples of still photos were a joy to behold. I also agree with him that film is a more pleasing medium than direct-to-video. Unfortunately, it would appear that budget limitations (and perhaps portability considerations as well, as photographers were slogging through wilderness) precluded the use of 35mm film, which would have been ideal. Instead, a decision was made (by whom I have no idea) that 16mm film would be the next best thing. This is the point at which I would have decided to use direct video. Even though it may be a little lacking in warmth compared with film, there is only so much grain that I am willing to put up with in a hi-def production. My consumer-grade HD camcorder makes much clearer and cleaner video than is seen in this series.
There are a couple of points to be made in favor of the Blu-ray version, however. First, those who may be basing their purchase decision on what they saw on PBS's HD telecast should know that the Blu-ray disc is somewhat better; the graininess of the 16mm film really messed up the compression algorithms used in the distribution of the telecast. Also, the stunning still photos, both the old B&W's that were probably shot on 4x5 negatives, and the modern color photos, benefit from Blu-ray versus DVD, if you're willing to pay the price.
None of this criticism of the video is relevant to the DVD; nor will it matter to those with poor eyesight or who watch on less than full-resolution HDTVs or who view from a distance greater than recommended for a given screen size. I for one was hoping for something visually splendid, something like "Planet Earth" or the BBC's "Yellowstone," something, quite frankly, that would help to justify my investment in home theater. The National Parks doesn't do it.