I greatly prefer the Wet Suit selection from New Leaf. The simplicity of the Red, Blue, and Orange ones was great, and the little insignias on the Black (anchor), Pink (palm tree), and White (crown) ones looked neat. I even prefer the Striped Wet Suit from New Leaf because I feel like the sleeves look better.
If I had to choose one as my favorite from New Leaf, I'd probably go with the Orange Wet Suit, since it's one of my favorite colors alongside purple and pink. It should come as no surprise, then, that Pink would be my second favorite of these.
Not really a fan of the New Horizons Wet Suits. I find the design of the Leaf-Print to be too busy, while the Striped Wet Suits are kind of ruined by the light blue anchor insignias. The anchor on the Black Wet Suit in New Leaf was fine since its yellow color matched the little yellow accents on the wrists. With these ones though, the light blue draws the eye and just makes them look awkward. As such, the one I like the most in New Horizons is the Nook Inc. Wet Suit, because it's just simple. I'm hoping that more colors and styles will be added in the future.