Managed photos stores the masters in the Aperture Library (which is a folder, and you can look inside and see your originals, but by default it looks to the finder like a single file). Aperture has a database of originals and your edits.
Referenced leaves the original photos in the location of your choice and only the edit information is stored in the Aperture Library.
I use Managed, because I have lost more things from putting them in "special" locations than all other reasons combined. With Managed, I know where everything is. I do export copies of my selects for online backup, but have never lost an original from the Library.
Best,
Matt
HI Matt
I use Referenced, because I have more images than I can keep easily in a managed library.
However - I keep all images on one 2Tb external firewire 800 portable drive (which then backs up to various places automatically).
The Referenced folder structure largely mirrors the project names within Aperture.
It has the advantage that my Aperture library is around 110Gb - and that fits happily on the SSD in my 15" MBP Retina . . . .
This has the double advantage that I can view my whole library even when I only have my laptop - also loading the library is much quicker.
When I go away, I import the files as 'managed' files - and then when I get home I relocate masters to the folder structure on the external drive.
I must say I've not been aware of this problem with exporting master files (but of course I don't do it that often).
Horses for courses - I still far prefer Aperture to LR5 - and it seems to me that the updates to Aperture have been since 3.0 have been about as significant as the ones to LR since 3.0 . . . . the only real difference is that one has had to pay for two upgrades to LR.
All the best