A fair number of folks have been asking about the differences between AE and Adobe's Importer plugin. Some highlights are:
- AE requires a working copy of Aperture 3.x, Lr is standalone (not sure about its database schema capability).
- AE maintains your Aperture hierarchy in the saved folders. Lr destroys that and saves it in a YYYY/MM/DD scheme.
- AE allows control over which images are saved with baked in adjustments.
- Lr saves images with baked-in adjustments by finding the Aperture preview files (low quality) and saving those.
- AE allows images with baked-in adjustments to be saved as high quality TIFFs or JPEGs (adjustable quality).
- The Lr importer tends to lose location metadata especially when added using Aperture's locations feature.
- Lr importer loses any version names you've added to your images. AE maintains them and can also rename the exported files based on the version name.
- AE can name images based on image naming profiles.
- AE saves metadata in a text file even when the original file is missing (offline).
- AE doesn't require Lightroom.
- AE's exported results can be used with products other than Lightroom.
- AE is actively supported and maintained.
- You can actually get support for AE.