First time I saw it I noticed the grain, etc in the dark scenes (a good example was when Anakin and Padme were talking in the dark on Naboo). The image just wasn't as crisp as I would have liked it to be.

Second time I saw it, I saw it in a theatre with digital projection since the image looked much much crisper and there was no grain to be seen. It looked fantastic.

I even made a point to see if it was there for my second viewing.

Lesson learned: See AOTC in a theatre with digital projection. It was like VHS vs. DVD

Lucky you, the closest digital theater to me is nine hours away.