Aperture 2 vs Photoshop Elements *

Was looking at Aperture 2 and was thinking of switching over from Photoshop Elements 8. What are the pros, cons and recommendations?

I find Aperture great for cataloging large numbers of files and making backups.

I don't have elements but know that PS won't do this. I think you need lightroom.

Think of Aperture as iPhoto on steroids.

Elements may be better for working with individual photos.