Walmart should say that these are on DVD-Rs. (Amazon does for season 4 & 5) The low ratings is a reflection of the unadvertised DVD-Rs.
They are very watchable but not the picture quality of the first three seasons (almost a VCR recorded quality to them). I would not have ordered if I had known this. Decided to keep them because I love the series so much.
Playing them on my PC, they do not behave as other DVDs. If I try to fast forward/reverse I am unable to return to regular play, must start over. Unable to move forward by clicking on the progress bar. Have not tried them on my DVD player.