I'm tempted to say "Dreamwidth!" too, because I know many of the changes made to LJ styles have been murder on kinkmemes -- threads that don't expand completely, ever; invisible subject lines, etc.

I really think it would depend on the fandom(s), though -- if there's a heavy presence on LJ, do it there; if there's a heavy presence on DW, do it here, and if they're split 50/50 then maybe promote it hard on LJ but actually hold it here?

*shrugs*