Recently moved 25,248 photos/video clips in my old iMac G5 iPhoto library to an external hard drive and then onto new iMac 27 inch, somehow resulting in 61,601 images in the new iPhoto library. Purchased and used Duplicate Annihilator in Magic mode to go after the presumed duplicates. It took 96 hours to complete and came up with 1394 duplicates. Spot checking, it did a good job of labeling a duplicate but not if there were 3 or 4 of the same image, it would just label one as a duplicate. I then ran Thumbnail Annihilator, it took 47 hours to complete and came up with 29,857 thumbnails. Do the math and there are still a possible 5,102 extra images not accounted for. I am not in the mood to search them out, so despite 143 hours of Annihilator work, I may clean out/reformat the new Imac and work with Apple support to transfer the iPhoto library. So I would say Duplicate Annihilator is easy to use but is very slow and not 100% capture.