Pain in the arse because there is no easy eay of determining which was the master. Instead of a hierarchy, you have a hierarchy with a temporal aspect as well poorly mapped to a non temporal hierarchy.

The metadata is still not opaque (its not stored with the files making backup/restore hard) and it lags meaning its potentially somewhere between ok and useless at any point in time.

Watermark, thumbnail, rename, move to a directory outside iPhoto, run a gallery script. Hell.

I ended up with ViewNX which has no abstraction and a python script using PIL instead of automator. Neither of which leverage any advantage that OSX portrays. In fact I could do the same thing on any platform.