When it first aired, there was supposedly something like 2 dozen factual errors that were later corrected in time for the video and later dvd release. The only things I didn't like was that it focused heavily on 3 teams far more than any other. Red Sox, Brooklyn Dodgers, and Yankees. It skips from the '67 Series to the '69 Series, then it glosses over the next few years until the 1975 series. And it took all of their info on Ty Cobb on Al Stump's now debunked biography of Cobb. David Okrent, who features heavily in this also appears much later in a documentary about Tigers' legends and he admits that much of what we knew about Cobb was either overblown or outright false thanks to the biography by Charles Leerhsen (A Terrible Beauty) that was actually researched. Apart from those the documentary is another gem in Ken Burns' belt and I watch it every year at the start of the baseball season and again around World Series time.
Review of Baseball
