One piece Character Designs?

Luffy: Either really; not THAT much changed; Luffy just started wearing long sleeves and a sash.

Zoro: That scar looks really becoming, and he looks more like a badass samurai now.

Nami: Both, because Nami-SWAAAN always looks stunning (lol, such a Sanji line)

Usopp: Post-time skip, 'cause he actually gains some muscle and doesn't look like a newb anymore.

Sanji: I like the goatee, makes him look more mature (even though he isn't xD)

Chopper: I prefer pre-time skip, mainly because his hat was given to him by Dr. Hiluluk (how could he have gotten rid of it?!). I like his new forms though, and how he can fight more on his own.

Robin: Not sure about her. I like that her post-time skip appearance has brighter, more vibrant clothes, which suggests that she has a happier, brighter personality. Except this isn't always the case, so I think her pre-time skip appearance fits better for those moments.

Franky: I liked pre-time skip, because he looked more human. I especially liked it when enemies would go "What the hell are you?!" whenever he used Weapons Left or Fresh Fire. Now it's too obvious that he's a cyborg, but I guess that doesn't matter, since his bounty poster says so anyway.

Brook: I like the crown, but not the sunglasses. His Doflamingo-esque jacket thing is cool, but I'm not sure if I like it more than his top hat. He transformed into a "gentleman" into a "rock star" essentially.