I'm very excited for git annex assistant. I've been looking for a few years for a "Dropbox with my own server" type of service that I can use to easily keep large files in sync.
There are a handful of programs like unison that do the syncing well, but don't have nice fsevent type triggers for all platforms. Git based programs like Sparkleshare don't work because git chokes on large repositories. Syncany seems to be abandoned. AeroFS was close, but it kept syncing huge files back and forth between my computers when they hadn't been modified. Now I'm eagerly waiting to try git annex assistant.
Oh man, I am so excited about git-annex assistant. As nice as dropbox is, it still involves far to much file-shuffling for me to get full enjoyment out of it. (Also, its new Android application is... unfortunate). git-annex assistant really seems like it will become the killer feature of whatever device you put it on though.
Do you know if you can still donate to his kickstarter campaign to get in on the betas? I know he blew away his goal and time is up, but that guy works for far too little.