I know I'm a bit late on this but I'd be remiss not to mention that Aperture 3.3 and iPhoto 9.3 can now share the same photo library. This is huge. My affair with photo library managers is long. I can tell you that switching between two applications - no matter how I tried to do it - took days to accomplish. Not anymore.
Aperture and iPhoto now share libraries
Monday, 18 June 2012