Also, what AC game do you mainly play?
Dialogue - AC
G. The villagers had a lot of personality. Also, the harshness got toned down too much in later games.
Villagers (not dialogue) - AC:NL. Although I do miss some villagers from older versions, I prefer the NL villagers overall.
Places - AC:CF. I prefer the city over NL's Main Street, although I would miss NL's separation of the Nook(ling) store and Re-Tail.
Customization - Need I say more than this image?
Gameplay mechanics - AC:NL. There is so much more you can do with the island and the role of mayor.
- - - Post Merge - - -
Forgot to mention that I mainly play NL.
Dialogue - AC

Villagers (not dialogue) - AC:NL. Although I do miss some villagers from older versions, I prefer the NL villagers overall.
Places - AC:CF. I prefer the city over NL's Main Street, although I would miss NL's separation of the Nook(ling) store and Re-Tail.
Customization - Need I say more than this image?

Gameplay mechanics - AC:NL. There is so much more you can do with the island and the role of mayor.
- - - Post Merge - - -
Forgot to mention that I mainly play NL.