i have a jazz, 2 precision, a ric, a gretsch, and an upright. if i had to choose between a j and p bass i'd have to go with the P especially coming from an upright. the J is brighter with more growl to it, the P bass is more rounded with a fat bottom end. they're both great basses and i'd say get'em both if ya can, but if only on P-bass all day every day (2nd only to my gretsch broadkaster)