Can't really comment on each individual episode so I'll choose this one. Seeing these people over time is indeed magical. They are us and we are them. Also terrific is the series as an historical documentation of Britain, which carries on throughout, albeit in more subtle ways as the series progresses.
Immensely appreciate everything about this series, but this installment more than the others provokes responses from its participants that is indulgent. Asking one if she wishes she were "better off," for example, puts a label on her that is the very thing this series is meant to be questioning. What's so successful about Seven Up is the simplicity of the questions and the complexity of the responses. Stick to that!