Conclusion: For under $80, Apple's Aperture gets you capable pro-level photo workflow and editing software for your iPhoto library.
Pros: Clear interface. Wide raw camera file support. Good organizational tools, including face recognition and geo-location. No import needed to use iPhoto library. Excellent output options, including soft proofing. Support for iCloud Photo Stream and MacBook with Retina display. Good value for money.
Cons: Weak noise and chromatic aberration correction. Minimal video editing. No geometry correction tools. Mac-only.
Excerpt: Aperture is often referred to as iPhoto on steroids, yet anyone who’s used it will have noticed that although it’s more powerful than iPhoto, it lacks many of the features that make iPhoto fun to use.
Pros: Vastly improved slideshows; impressive new brushes; multi-touch aware; ability to split and merge libraries; easy export to Flickr and Facebook
Cons: Sporadic reports of potential problems when upgrading older libraries; web page creation hasn’t been overhauled; need a powerful Mac and lots of RAM to run well
Conclusion: Aperture 3 is undoubtedly a good bit of software with some excellent features added to the last incarnation. However, it is hard to see many professional photographers and enthusiasts switching from Adobe Lightroom or Photoshop to go through the hassle of learning another software package of a type...
Pros: Effects brushes with edge detection work very well plus welcome additions of Faces and Places from iPhoto
Cons: Not easy to get to grips with and often frustrating to navigate around; some superfluous features
Conclusion: If you work on a Windows system, the choice between Lightroom and Aperture is easy; since there's no Windows version of Aperture, your choice is made for you. On a PowerPC G5 or G4-based Mac, Lightroom's less demanding system requirements make it the more attractive alternative.
Pros: No Windows version, Relatively steep hardware requirements, Limited Apple support options, Restrictive file-management system, No curves view or editor
Cons: Excellent retouching tools in a streamlined interface, Delivers great results, Integrated colour management