I like them all a lot, but the green one is definitely my favorite. The deep, forest green shade is great and it goes well with forest vibes. I like the orange and yellow ones a lot too to add a pop of color here and there.
Sadly I haven't used the white variants yet since my island is half lush forest and half urban, and the white pumpkins don't really go with either. I'll probably use them more in the winter as little lights spread out in my forest, since they'll blend in well with the snow and the glow will look great on winter nights.
monochrome and the classic orange are my favourites. the yellow ones dont even look that much different to their orange cousins and to be honest they look uglier. The only decent green ones are the pumpkin lanterns, towers,spooky lamps and arches. the rest...meh
I've customized all my pumpkin pieces of furniture with the monochrome variation. I like the default one too, but monochrome looks classier. I also dislike the green and the yellow variations.
I like orange. No only the color, but also I prefer the faces of the orange pumpinks. But I am using green arches for the entrances of the forest. They look specially good after or before a wood bridge.
And when night comes and their light is on... they look orange to me anyways!
My favorites are definitely the monochrome, i've got a little area dedicated to growing just white pumpkins and the decorations around it look fantastic ! I also just like how unhappy the faces look as well !