I have a JF but it's empty and there just so I can can play in fandom_wank. It always baffles me when people friend it.

Also, my LJ has content that my IJ does not, but mostly it's fandom-specific stuff and fic, so if you're not into it, then sticking with IJ is fine. (I kind of hate logging in to IJ because of all the ads that make it so flipping ugly and use that site as a mirror more than anything else.)