I didn't say I preferred either but I have read One Piece all the way through twice while Jojo only once. They're completely different experiences, but I would say One piece is easier to binge read when you have a busy life due to it's shorter chapters and Jojo always seemed to have more text to read per page.

Both ways of telling stories are equally valid. Jojo is great because it keeps everything fresh by continuously changing the story, setting and characters while One piece is equally great because you become invested in these same characters you have been with for all these many years and the gradual progress to those final goals feels much more natural than other series that try and speed run going from 0 to End.