So I’ve been playing with both of these programs for the past two months, and I initially bought Aperture because the demo was 10x’s better than the lightroom demo. This may be because I only have a 1GiG of RAM, but lightroom takes alot longer to render photos than aperture does, and I get the “beach ball from Hell” quite a bit more often.
As a result of that, I love what aperture can do for archiving photos. However, Lightroom is a much more powerfull editing tool, (from what I have seen) and the ability to be able to have presets that work in Lightroom and the scrollover tabs to see what the photo looks like with different presets, is much more useful for me, when it comes to quickly editing photos.
On the other hand, Aperture has a much faster way to edit down your favorites, and discard the photos that you do not like, than Lightroom does.
I dont have the answer as to which one of these programs is the right one. I think that Aperture is Awesome for archiving, and Lightroom is awesome for quickly editing with presets. If there is a way to then transfer your selected images into Lightroom from Apeture, I think that is a really fast way to get your selected images ready for review.