iPhoto is Apple's default photo management solution. I have used it since early 2004 when I purchased my first Mac. I currently run OS X 10.6.8. and iPhoto '09 (iPhoto version 8.1.2 Build 424). In late 2013, this is considered an old version of the OS and an old version of iPhoto. I have seen more recent versions of iPhoto as my wife runs 10.7 and a newer version of iPhoto.
In the spring of 2012 I purchased a Cannon t3i and started to shoot RAW. (Read large photo size and editable images.) So, I need a photo editing solution with more power than iPhoto. My iPhoto collection was also starting to wax big approaching 28,000 images at the time (and why not after 9 years of collecting photos).
iPhoto is a brilliant way to browse photos and gives great access to simple tools to crop, rotate, and apply redeye reduction. However, iPhoto has a weakness when it comes to embedded metadata. If you want to export your photo, with geo-tagged location, and with keywords applied then one needed to export the photo as a .jpg. And one could not apply these metadata "enrichments" to the original photo file type. iPhoto's "Export Original" is just that, the original file, not the original plus added metadata.
Enter Lightroom. Lightroom gives a lot of access to editing photos, and to metadata options. It supports EXIF, IPTC, and XMP metadata. I had previously tried Apple's Aperture 2.0 (I own it). And had downloaded Aperture 3.3 trial. I felt that the capabilities (especially geo-tagging), and workflow options of Lightroom 4 exceeded those in ApertureI still find PhotoLinker to have the best UX and the clearest workflows related to metadata enrichment of photos. I have been using this for several years to write metadata to original images in iPhoto where, iPhoto wont natively allow the editing of certain metadata elements.. So, I got Lightroom in the fall of 2012. By fall of 2013 I had shot 12,000 RAW images. I needed to stop living the double life of iPhoto and Lightroom. But what was I to do with 9 YEARS of annotations, edits, and geo-tagging which I had applied to my images? How was I supposed to liberate these annotations out of iPhoto?
After some intense googling I found Phoshare version 1.4.7. A brilliant Open Source app created to liberate iPhoto data and apply it to exported images. I followed the instructions and it works wonderfully! From there I am using Lightroom's import features and importing the photos to LightroomThe one thing I wish Phoshare did was embed the iPhoto Event Title in the photos. There is a spot in IPTC metadata for Events, but event reducing the Event Title to a keyword would save me the titles on over 1500 events.. If I had upgraded my iPhoto library to a newer version of iPhoto, Phoshare would not work. However, it might be possible to convert newer iPhoto libraries to older iPhoto libraries with iPhoto Library Manager. The most annoying issue with the transfer of photos has been the need to disassemble iPhoto collections (albums) and smart albums. I had over 200. I ended up creating new keywords which would be transferred to Lightroom. I then exported all the images via Phoshare, and exported them into folders according to their iPhoto events. This allowed me to import them and apply a tag with the event name in Lightroom.