Well, Wano's the bottom of the list. Wano's got problems. It just went on too long. I didn't care about most of the new characters they introduced. It's really the only arc I dread revisiting. And between my problems with the main Wano arc, and Yamato's cover story just not really going anywhere, I'm still just kind of sick of Wano in general. So, that gets the bottom slot.
Egghead versus Whole Cake is a little tougher for me, though.
I really like Sanji's story during Wholecake, it's been a while since a Strawhat who wasn't Luffy got a major focus in a arc. I even really grew to like Pudding. And Katakuri's a good villain. And I really like the twisted fairytale vibe of the island, it's a fun place to look at. Big Mom's backstory is probably one of the more memorable villain backstories. But, I'll admit, Big Mom getting obsessed with her Wedding Cake dragged on a little long by the end of the arc. And I really never cared much about most of the other Charlotte Family. There's so many of them that they just kind of blur together, for me.
Kuma's backstory is probably the best thing about Egghead. It's the arc that made me care about Bonney as a character. And we got so many lore reveals during the arc. It's first time we got to see Vegapunk after getting teased about him for years. And I actually like most of the Satellites. I really like a lot of the Strawhats new Egghead outfits. We finally started learning about the Gorosei after decades of them being hidden in shadowy rooms. We got to see Lucci and Kaku again, which has it's pluses and minuses. Vegapunk's speech being a bit of a dud kind of drags the arc down a bit, though. And it's kind of a shame that the future technology didn't actually play a huge role in any of the fights. I think Egghead has higher highs than Wholecake, but also lower lows.
I think for the sheer amount of stuff that got crammed into Egghead, I have to put that on top.
So, for me, at least right now, it goes:
Egghead>Wholecake>Wano.