No, the Joker series in the '70s was an ongoing but was cancelled with #9. I've read it and it is pretty weird: the Joker isn't all that much of a bad guy. He doesn't kill anyone or even do anything all that bad. Pretty much every issue ends with him getting captured and starts with him escaping from prison.
As far as Harley goes, I used to dislike her a lot. Now that she's sort of evolved into this anti-hero role with an established fan base, I don't feel the same way. I'm just sort of neutral. She's not for me but given her popularity she clearly fills an entertainment niche so that's cool.