Given the options, I'm personally in favor of keeping the fest on IJ. If you haven't noticed it already (and someone had to point it out to me before I figured it out), IJ has a regular daily down time at 1:30 pm EST that lasts for less than 30 minutes. It's pretty reliable otherwise. I just spent a month posting for Kinky Kristmas, and never had any problem whatsoever.
I do have a DW, but don't use it because no one seems to do anything there but crosspost what they're already putting on their LJ or IJ. A lot of folks haven't even bothered to get DW accounts, or have them but never bother to lot into them. I suspect it might not be the best place to get participants/watchers/commenters.