For me, it depends. Sometimes color enhances the experience, but classic black and white manga can have its own charm too. It really depends on the art style and the story.
The majority of manga are not in color. It's a common practice in the manga industry to use black and white for regular publications. But for certain limited series or special projects, color might be employed to make them stand out.
The JoJo manga is mainly presented in black and white. However, there might be some special editions or colored illustrations for promotional purposes, but the standard version is not in color.
One option could be to check if there are any officially released color editions of Bleach manga. Sometimes publishers come out with special colorized versions. Another way is to search on dedicated manga reading platforms, but not all of them might have the color versions available.
The One Piece manga is not in color. It's presented in black and white, which allows for greater focus on the linework and details of the illustrations. Colorized versions might exist in some limited cases, but the majority of the manga is black and white.