I have watched a couple of these. They're nice for the fans of a particular director, but don't cover much you wouldn't already know. They're a little too congratulatory to the person being covered to be taken seriously, not to mention brief when you're coving a career like Spielberg from the late 60s to Saving Private Ryan. The quality is very plain, with the quality of the clips inserted varying wildly. Lots of interview footage of the directors and selected guests (people who have worked with the director).
We have reviews of most of the series up at http://www.digitallyobsessed.com
They're pretty good, in general, and make a nice introduction to the director's work; they won't suffice for the devotee, but what do you expect in a 1-hour program. I think they should do them as double features myself instead of taking up space on the shelf. I particularly liked the Spielberg and Roger Corman discs.