Though the motion pictures are much better (not to mention the manga), the old TV-series is not bad also. There is nothing new for those that have already read the manga and seen the films, but still it's quite good to watch. Kinnosuke Nakamura's sword skills are of course also inferior to those of Tomisaburo Wakayama's, but is still think he's done a good role. In all dimensions it's cheaper and cheesier than films (i mean, Wakayama's eyes reek of death when he's cutting down the countless enemies - nothing like this in here). But the stories are much more in-depth than in films, and also - there's more of them :) which is definitely good. Also, the setting and the life of medieval japan is also much more explained than in the films - in that it resembles the manga.
Anyway, if you like Lone wolf & Cub and you have the spare time, it's definitely worth to watch.
