One thing to be noted at the outset, this is not the complete series with the episodes as they aired. This is a repackaging of volumes 1-3 of the Mike Judge Collections, adding the fourth volume which was the limited run season that aired in 2011, and then the movie that was made during the original run of the series. In volumes 1-3 each volume is split between two discs. The first disc has the episodes and the second disc has the music videos that they could get the rights to. Anyone who watched the series in the 1990s, when it was originally on MTV probably remembers that in each episode, in breaks in the story, Beavis and Butthead would watch, and make fun of, music videos. Because of licensing issues, they could not get the rights to all of the videos that originally aired, so the solution was to remove the music videos and show just air the storylines (so each episode ends up being about 20 minutes long, give or take), and then showing the music videos on disc 2. It should also be noted that not every episode that aired is included in the set. Most of the episodes that aired are included, but there are some missing. For the fourth volume, which is the 2011 season, all of those episodes are included as they aired. In that season, instead of watching primarily music videos, during the breaks in the story, they would watch, and rip on the MTV reality shows.
The DVDs carry over all of the extras from the original individual collection releases. Those include deleted scenes, promo spots, and special appearances that Beavis and Butthead made (such as at the MTV music awards), and a multi-part behind-the-scenes/making-of retrospective where the creators of the show discuss how it was made, the influence on pop culture, and the like. The movie has a commentary track by Mike Judge which is really good, and the extras for the fourth volume include a good discussion from the Comic-Con panel between Johnny Knoxville and Mike Judge.
For most people, the show will probably be a blast from the past. You definitely have to enjoy juvenile and sometimes stupid humor, but masked in the humor was a commentary on topics like political correctness and the topical events that were happening in the 1990s. It is disappointing that not all of the episodes are included, and we cannot get the complete shows, as they aired, but this is probably the best set that is going to be released. So, if you were a fan of the show, it is definitely worth the pickup.