Robin was definitely the best in my point of view, a complete change and it suits her a lot.
IJ got a really cool style, which is standard for sanji, at first I found it annoying knowing it was the same thing that the DJ only with a few rays, but after the cover of vol 102, that is beautiful, I hope to see a hell memories with these flames.
Luffy's style was also interesting, it matches him a lot.
Zoro's was a little too standard, it's the same thing, only with CoC and an energy that looks more like smoke, cool but not so impactful.