I have the same issue. My photos stopped on Nov.9th.
I just deleted and reinstalled version 3.1 and it took 90 pictures from my Photostream and transfered them to my PC
Thing is that I have 318 pics in my Photostream. The synching works fine between my iPhone 5S, iPad2, iPhone 3G and iPhone 5.
My wife is getting a iPad Air for Xmas so no idea of how it will work then but I assume it will be no problem.
I have Windows 7 and so does my mom on her laptop and PC which I also connected so I don't have to send her pics but she can just check. I had to update both machines to 3.1 and they only grabbed 85 pictures.
This is quite annoying when you live 500 kilometers apart and all worked fine until the latest updates.
Please Apple fix this asap as it's a lifeline for families all over the world