Photo Stream not working on my Mac since upgrade to Mountain Lion

I've noticed that Photo Stream isn't downloading new photos that I've taken on my iPhone since I upgraded to Mountain Lion. My iPad is syncing just fine. I've tried both iPhoto and Aperture on my Mac, neither seem to be receiving new photos in the stream. Also, I deleted a bunch of photos from my stream inside Aperture, those deletes haven't propagated to my other iOS devices.

Anyone else experiencing this issue? Is there is a known workaround?