I have the same problem. The drawing looks so childish and it's pretty childish in the begin but I am now at episode 69 and I am going to like it more.
The story looks good up till now and it's pretty fun even I think sometimes they are making it too fun..
It was hard for me to keep watching it at the begin but if you got enough free time you should watch 20/30 episodes.
7/10 for me.
Well yea, its childish. Oda doesn't put so much effort into his drawings, he focuses more on the story line, humor and action. But after watching it alot, the drawing style doesn't really bother you. It's different for everyone, some get used to it at 20 episodes, others at 100.
Don't compare the art style to any anime you've ever watched.
Kubo focuses TOO much on the drawings, storeline sucks, each chapter is too short. Oda could fit a whole Bleach chapter into two pages.
Naruto was pretty good, but it's coming to an end, and everyone is waiting for inevitable final battle.
And Bleach and Naruto have too much crappy fillers.
Naruto: nearly everything
Bleach: half an episode
One Piece: never
never say never..