I don't see this as an "arguement" ... people come to TB for ideas and perspectives that might help them choose instruments that will make them happier. So I was just trying to represent a point of view that I've come to after playing hundreds of instruments and doing a fair amount of gigging, recording, and listening.
I think they sound different, and I can get into lots of theories I have as to why, but they just do. I was a fairly early adopter of 5 and 6 string basses and still own a bunch of 5'ers, so I don't mean it as a knock against 5'ers or the people that love them.
I also think the neck pickup on a J doesn't sound like a P, and that there's a different "right" set of strings for every different bass, and that every individual instrument sounds a little different from another that has identical specs.
And I also think you can handle your gigs on pretty much any bass, and your time is probably better spent practicing than talkbassing.
Opinions are like bellybuttons.