I've been shooting JPEG for the past few days with the D90, and I must say, I am quite impressed with the quality as I sit here and wait for RAW support. You are right regarding having to fuss less in Aperture post wise. I could actually get used to this, and I've been shooting strictly RAW for the past few years.
Mmmm, maybe I need to start shooting RAW+JPEG, and only keeping the RAW file as my digital negative, while extracting the JPEG from within Aperture, stacking right away on initial import! 8-)