I managed to have all store worlds, and here's my personal opinion:
Lucky Palms wins. It has a great amount of empty lots, cool neighbors and room for other expansions.
Aurora Skies is my second choice, besides the lack of more room.
Dragon Valley is my third, since it's beautiful. However, you end up with a bunch of elves. Maybe Monte Vista is better, but I got more involved with Dragon Valley, that's why it's better for me.
I didn't have much experience in Midnight Hollow, Roaring Heights and Lunar Lakes
Sunlit Tides has a bunch of micro lots. I hate that because I can't add several buildings I always use (I have to rebuild a bunch of micro lots or some huge stuff, it's not really balanced). Hidden Springs was a bug-fest for me. Barnacle Bay is sort of bland for me.
I'd suggest checking some videos on youtube about the neighborhoods. I've got them all because I did want it, but nowadays, I've got only Lucky Palms installed.