James Duncan Davidson has a few words to say on using Lightroom Vs Aperture.
“Over the last year or so, I’ve been a very casual user of Lightroom. Mostly, I’ve been using it enough to keep tabs on its development and write about it. But, the majority of my work, as well as my primary image library, lived in Aperture. Then, sometime late last year, I discovered that Lightroom is a great vehicle for making large prints from. In comparison, the prints from Aperture look a bit, um, mushy for my taste. The differences in my comparison prints can be described as looking at a good picture taken with a kit lens next to the same scene taken with professional glass. So, I’ve been using Aperture for almost everything, but using Lightroom to produce big prints from.”
Via Inside Lightroom