Hi Mary,
For your first requirement of "leads who were not delivered a certain email":Both filters you have shown will behave exactly the same. I personally would use the "Not was delivered email" filter along with "email is" as it is just a more direct statement.
For the second requirement of "are not members of an engagement program":The filters shown will actually behave differently. The filter of "not was added to an engagement program" looks at a leads entire history. Therefore, if a lead once belonged to a program but is no longer a member, they would be excluded via this filter and the way you have it set. This is because they were in fact once added to the program in the past.
I assume you wish to more specifically target current day non-members of a program. If that's correct, I would use the "member of engagement program" filter exactly the way you have it configured. This only filters based on program membership specifically at the time of cast or trigger event.
Hope this helps!
-Kai H