@unrealnighthawk

I would also suggest Goodsync as a valid alternative. There are versions for PC and MAC available.
Their technical support was not very responsive though when I had some questions on making it work with my Pogoplug/Docktar.

I tested a couple of backup and sync software alternatives here: http://www.pogoplugged.com/forum/thread/11615/Pogoplug-Compatibility-List-Bac...

I had the idea to actively sync (both ways) between a MAC, a PC and a Pogoplug all connected to the same network. Using Goodsync I got this setup to work.
I made on all 3 devices a folder that was kept in sync all the time.

It worked pretty well. I had to test for a while before I got all the Goodsync settings right on both Mac and PC. But I would suggest you to let Goodsync make backups of the files it removes from the folder. It happened a few times that something went wrong in case two files where removed or changed location simultaneously on both computers...

I also consider syncing as a feature that has to be integrated in the Pogoplug driver. This is one of the limiting factors of the Pogoplug compared to Dropbox.

The reason I'm not using Goodsync anymore is because I just tested it with a trial version and didn't want to spend money on two or three licenses.
There are often some coupon codes available to make the purchase considerably cheaper but I'm hoping a next driver update by Cloud Engines will solve the issue all together.

@threewater - Glad it's helped you! I'm still keeping my fingers crossed for the day when Pogoplug can actually do multi-directional sync on all platforms like Dropbox (I'm a Linux user). Not sure why it's taking them so long to include this capability.