I've got a friend that shoots Canon and has always even to this date uses Aperture to work on his images. Personally, I use LR3.x/ACR and I've also used Bibble and Lightzone (linux versions). If its just to process the files then Biible, Lightroom, ACR, Aperture, capture 1 etc are all pretty cool and it then comes down to which one works for you and gives you the IQ to your files.
If however, you want to manage your images as well, then Lightroom may be the one to get - I'm pretty much hooked into the way the image managment and then PP development work flawlessly together. I don;t have any real knowledge on Aperture so can't comment if it does the same but did have a pretty similar setup with Linux - Picassa + Bibble/lightzone so you could do the same on a mac. If your only interested in Aparture or LR, then I'd say LR .. also Adobe update LR more frequently than Apple so you may want to take that into consideration.