Both basses have their faithful followers, I personally like both, I swing more for a P these days as the sound is thicker (as is the neck) and I'm in a 3 piece band. Both have their merits and flaws, just depends on which one has more pros than cons to you. For example, I find the first volume pot on a jazz gets in my way when playing with a pick, on a P the nobs are further away, but I miss having the jazzes back pickup for a thumb rest on a P. The major thing for me is the neck though, not enough substance to a jazz neck. Give me a planed baseball bat any day.