There are several advantages of this high-quality BBC dramatic TV series being on DVD:
Pause, fast forward, or rewind at any time.
Broadcasters or cable operators cannot use an embedded digital "broadcast flag" to trigger a DVR's recording shutdown or file deletion (I used to think the likelihood of this was quite small but now I'm not so sure.)
The stories center on Detective Foyle, a senior police detective in southern 1940 wartime England. While the war is progressing (this is before the U.S. came in on the Allies' side) life must go on -- and laws must be enforced.
Foyle is one of those mature loner types (a widower) who has seen it all, done it all, and now finds himself, despite his location far from London, tied up in investigations where home front politics and World War II inevitably intersect.
The intertwining of story lines related to family, friends, town, and war is one of the most impressive things about this series. Also impressive is the recreation of wartime England. Some of the production notes indicate the level of effort put into making sure costumes, sets, and outdoor scenes look and feel real. We even see vintage aircraft occasionally including what seems to be a swarm of Spitfire fighter planes in the distance.
Finally, though, the stories are literate and well plotted. If you like history and police procedurals, and you like good characterization and a good script, this series is for you. (I would also recommend, as a good companion piece, the movie Enigma which is based on the excellent novel by Robert Harris.)