First of all, Universal Studios received tons of complaints about the audio quality and a recall was issued. One disk and episode was particularly bad, so they've agreed to send people a new one. By this time (late July), there shouldn't be very many, if any, left in circulation.
Bear in mind, this is a show from the 1970's -- the audio/video quality weren't exactly top-notch the day it was filmed. Since then, the original copies have sat in the studio's vault. Considering this, the quality is remarkably good, but no amount of digital enhancement will ever produce a superb version. If you DO happen to get one which is really bad, don't hesitate to return it and make sure the store knows about the recall. (btw, I don't work for the store or the studio, but this information can be confirmed in reviews on other sites).
As for the show itself, five stars may seem excessive to a lot of people, but this is a childhood favorite of mine! Yeah, it's got all the hallmarks of classic 70's cheesy TV, but it's still very entertaining. Some of the stories are pretty awful, but the best ones more than make up for the worst. Given the bionic leap technology has made, they predicted amazingly well how bionics would actually work 35 years later.
My favorite story, "Doomsday Is Tomorrow," ranks in the top three best TV sci-fi I've ever seen! I made a VHS recording of it in the 80's, which I watched so many times that the tape broke!
Overall, if you keep it in perspective of the era and let yourself enjoy this show, I highly recommend this show!