OK most likely the wrong forum and I'm jumping to a conclusion, but anyway I thought I would share.
I was just processing an old 1DsmkIII file shot at 1600iso in poor light, I was wondering wether to send a low res onto a client as it was a bit noisy in the shadows. I decided to send it. The latest version of Aperture asked me to reprocess as it was originally processed in an older version. So I did and b ugger me the noise vanished, I checked I had nothing cranked up or any detail followed the noise out of the door, nothing obvious at 100% detrimental to be seen.
I had considered all these "reprocess" requests a bit of a chore before, but this looks like a big help. I have thought for sometime Aperture does a better job with Canon files than Adobe manages.