I got this response from AncestorSync customer support this morning. (I had also e-mailed them a year ago).
Ben,
AncestorSync currently lists the following programs as for synchronizing with Geni.com.
Ancestral Quest 12, Family Historian, Family Tree Maker 2008-2011, GEDCOM, Legacy 2-7, MacFamilyTree, PAF, RootsMagic 4 and 5 and The Master Genealogist 7 and 8.
We are doing some intensive updates and you may or may not have some success using AncestorSync right now. In fact, I have been told not to try testing it now since it's not working all the time. This may go on for another couple of weeks.
I suggest you join the Geni discussion for AncestorSync so you will know when we're ready to start testing it again. To find these discussions, log into Geni.com. Click the Research tab and choose Discussions. IN the Viewing: window, choose All Public. When you see the list of discussions, use the Search Discussions window and enter Release Candidate. The one called 2012.06.19 - Release Candidate 1 is the current discussion but the name may change if we make another version and call it Release Candidate 2. I will keep your ticket opened so I can try and let you know when we're actively testing again.
To download the current installer for AncestorSync, please go to http://ancestorsync.com/ and click the Join Our Beta button.
Thank you for being willing to test AncestorSync on Geni.com.