I'm staff of one of Brazil's biggest One Piece sites http://www.pieceproject.com/ , and also moderator of the Orkut comunity, so I think I can say something about how things are around here.
As everyone already knows, One Piece here is also 4kids version, so, pathetic. Because of good years for anime around here, like, some 10 years ago, I think it's a lot easier to make new fans because of the anime instead of the manga, but, as it sucks hard on tv, it's though for people to like it much. As for the manga, I started reading One Piece a lot of time after it began being published, but as far as know, it wasn't very much advertised And without the anime together, as it only started some 3 years ago in here, so I think it didn't sell that much. To make things worse, nowadays it has stopped beign published, cause Conrad Releaser broke. Everytime I can I try convincing people to read One Piece, and I've made a lot of pepole fan of the series, but they are like, afraid of the amount of chapters most of the times. Besides, Naruto is ninja manga, kids like that stuff, Bleach is sword fighting manga, almost everyone likes that, but One Piece beign a pirates manga doesn't catch that much attention.
Well, if you want to guide your friends to the One Piece side of the force XD, I suggest you try the showing them the japanese angle. Number of copies sold and so on.
Naruto and Bleach may be nowadays so called rulers of ocident, but One Piece is still the Imperor of the orient, and is much farther from finishing than the other two series. I still look forward to seeing One Piece as a global fever, and, with Viz Media releasing the mangas at the rate it started this year, this dream may come true.
Sorry for all the talking and not so good english.
say hi to cole :3