Aperture review: non-destructive editing for JPEG and TIFF

I was surprised to see that Aperture does non-destructive editing for JPEGs and TIFFs as well as RAW. Overall this is a very clear and valuable review:>

Art of RAW Conversion #022 @Digital Outback Photo

... Non-destructive editing Aperture does not modify master files but stores all modifications as a separate parameter set. Thus, you may have several versions of an image (master file). This is not new in RAW converters (e. g. RawShooter offers snapshots for this task), but Apple extends this concept from RAW files to JPEGs and TIFFs, as well ? it?s primarily intended to be used for files from your digital camera or scanner, but may be used for other files, as well.

I'm waiting for the promised patch release with some cautious optimism. I may even buy at that time.