Here's what's in it though:
Recommended for all customers using iPhoto 5.0, 5.0.1, 5.0.2 and 5.0.3. iPhoto 5.0.4 addresses an issue with browsing photos that have been auto-rotated by a camera.
5.0 gave us new features but could corrupt iPhoto 4 libraries on import
5.0.1 fixed the import from iPhoto 4 bug but made large libraries unstable
5.0.2 fixed the instability but gave us the colour shift bug
5.0.3 fixed the colour shift bug and gave us the weird crash/duplicate of rotated images when imported
Weird though how you wait 2 months for an iPhoto update and then 2 come along in a week or so...