It's been a while since I've chimed in on this, but I liked The Munsters better simply because it was more flagrantly funny. The M's were not without repetitive humor, but the A's thrived on it one ep after another-- every one they would mention needing Lurch for something and within a few feet would be the hangman's noose they would 'ring' and Lurch would immediately appear and say, "Youuu rangggg?", and there would be that sound and Morticia would say "Ah! the mail's in" and 'Thing' would arise with the mail. Were we supposed to laugh at these every time, as the laugh track prompt us?
I suppose it comes down to: do you like satire [Addams Family] or spoof [Munsters]? For me, it's spoof, and therefore The Munsters.
As a child, I was never afraid of Herman except when he turned into the hairy monster in the Zombo episode. On the other hand, I couldn't watch The Addams Family very much because Lurch gave me nightmares. He reminds me of today's Slender Man, who I find terrifying to look at as an adult.