That's really not something we can tell you.
What are your favorite/least favorite parts of Animal Crossing? For me, HHD was a must-buy because it expanded on my favorite parts of the franchise (decorating, planning, cute animals), and got rid of all my least favorite parts (the endless grind for bells, being forced to play every day or else my favorite villagers will move out, running out of stuff to do if I feel like marathon-playing when I'm in a bad mood, etc).