I prefer the design on the right because it looks unrestrictive, free and light, which suggests daytime activity and warm weather (all the more appealing in midwinter). Cape and high waist are great. The short skirt and hair length also seem more casual and playful, thus youthful, "cute". Love the skirt's little flower petal flips! The longer skirt on the left is a bit more elegant, thus mature, "serious".
There are several things I prefer about the design on the left. Most of all, I love the branching headwear/horns, which suggest an elf or dryad. I also agree with
@BakedBanana about the hip wings, very cool. Plus the left has much better shoes (I never like asymmetrical leggings). The draped pearls on the right don't really do much for me either. Maybe a hip bag?
This is very nice work. I probably sound nitpicky, but both designs are excellent