Haven't seen this show in about 30 years, though I swear I've had the these song playing in my head non-stop all that time.
Bonnie Franklin is the big surprise. She absolutely shines here. The seventies was an era when stage cliches became sitcom cliches, and this is a pretty good example of that. Seriously, how many "there's someone at the door" gags were there in this pilot episode? Everything and everybody around her seems strained and artificial, but she makes it all seem like an interesting comment on real life. She even makes that hairstyle work!