"American Experience" benefits (or suffers) from the fate of many documentary series, it can be disjointed as the installments are produced by a host of different people and production companies. This is especially evident in the first ten season, topics could range from personal stories to environmental advocacy to to more academic treatments of Presidents and natural disasters.
The original executive producer (the late Judy Crichton) has said that originally the series was conceived as a chronological trip through history, but as with many PBS programs, funding and self-interest gets in the way. The depth of twenty plus seasons would never have been possible given a "beginning to end" approach.
And that is not all bad, where else can a viewer see a treatment of Mormons, heart surgery, Tupperware, floods, and Coney Island all in one program? The sweep of American history is certainly grand enough to include all these things, and the fans who have witnessed it through the years have mostly seen the rewards of a more eclectic approach.
While history of any type might seem to be be boring to many, I would recommend the in-depth treatment of "American Experience" over glossy biographies and minor popular subjects seen on competing cable channels - even if it takes watching a few episodes to get "in the groove".