I just shot a wedding and spent a good deal of time rating over 3,000 images in Aperture 3.3 with the intention of handing the library over to another photographer I work with for post-production and delivery.
But then I discovered that he hasn’t upgraded to 3.3 because his Mac Pro is too old to accept it. It’s only about four years old and otherwise works just fine, so he’s not going to spend a ton of money just to upgrade Aperture quite yet.
It occurred to me that if I exported my original files (not jpegs) and selected “Include IPTC” my ratings should stick and be readable by him in in Aperture 3.2 once he imported them. I wasn’t sure about this so I did a test.