Father Knows Best, just like LITB and Dennis, has held up great for me. And I love O&H and the first couple of seasons of Patty Duke. The 3rd and final year didn't hold up as well.
The most prominent example of an older show not holding up for me was The Lucy Show. Season One was great. Two started going downhill. Three was barely watchable. And I have no interest in the California years even though I loved the entire run as a kid. Same with Here's Lucy. Didn't hold up at all for me. But to each his own and I'm happy all the Lucy stuff has been released for fans of her different series.
Gary "I think most of us have shows that haven't held up for us" O.