According to a random poll taken between the 27th of March and the 3rd of April 2008, One Piece ranks as one of the best manga as far as emotion, making people want to cry and readership recommendation.

The pirate manga series plays tag with the basketball manga Slam Dunk for top answers. Participants were free to choose any manga they wished. Females tended to gravitate towards One Piece than males, though there was a conciderable amount of support from both genders.

The survey can be found here.

((Accidently updated this on my personal world. Sorry for confusion!))