[Wulifou]

LR 2 and Aperture 2 are both fantastic products. I personnally prefer Aperture because of the UI, and mainly because of the simplicity to interact with my .mac account (webgallery, books ....)
I you don't need these features, then deciding between the two products will be a tough call. Several excellent plugins are already available for Aperture (e.g. NIK, Tiffen, Noise Ninja) whereas you can find tons of (more or less) usefull one-click-presets for LR, which can be a real timesaver. You definitely should have a look at these : https://www.pentaxforums.com/forums/post-processing-software/42221-k10d-k20d-...0081120-a.html
IMO the Pentax software can't be compared to these products in terms of efficiency and features.

[clawhammer]

Take note that aperture uses the graphics card for a lot of it's processing, so the cheap integrated graphics cards on the Macbooks aren't the best for running aperture. The new Macbook with the nVidia 9400 graphics chip in it should be better.

That being said, I run aperture on a 2.16ghz Macbook with the intel 950 gpu and it is bearable. Aperture 2.0 really did speed things up (especially with the Quick Preview function).

[jro]

Another vote for LR. Heaps cheaper than Ap.

A quick search on Google says $90 for Lightroom and $140 for Aperture. That's not that much cheaper.

I personally use Aperture because Apple generally looks after its apps fairly well (and often abuses their position as the maker of the OS, cf. Microsoft), while lately I've felt like Mac support from Adobe is an afterthought.

[a a i b]

I run Aperture. Impressed with its organizing logic in particular. It does require a more advanced system, however.

[WJW]

Take note that aperture uses the graphics card for a lot of it's processing, so the cheap integrated graphics cards on the Macbooks aren't the best for running aperture. The new Macbook with the nVidia 9400 graphics chip in it should be better.

That being said, I run aperture on a 2.16ghz Macbook with the intel 950 gpu and it is bearable. Aperture 2.0 really did speed things up (especially with the Quick Preview function).

I use A2 on a Macbook CD 1.83/GMA 950 and it runs OK. The main things I notice are that generating the original previews is slow, cloning/retouch can be slow, and a complete vault update can be glacially slow. So, I set the files to import and go have lunch or something and come back and go to work. If I need to update the vaults, I set it going when I am done with everything else and let it run overnight.