No experience with Aperture but I have been using Lightroom since it first was released.
It's a great compliment to PS. I still like to use my sharpening actions (not mine, but the one that I got from Fred Miranda) in PS since I think that they provide superior results but I do all of my exposure, color correction,burning/dodging, etc. in Lightroom now.
The batch processing is great, as I assume Aperture's is.