I current have LR4, no problems with it. I enjoy using it and integration with PS is great. However I find it to be a very resource heavy. CPU fires up. Always globs of RAM used. This is fine on my desktop and my MacBook Pro with tons of CPU power and RAM to spare. Now I plan to only take my MacBook Air on my next trip. Never used Aperture (well I did for a few hours when it first came out, but returned it because I didn't like it). Processing power is limited and RAM is stuck at 4GB with much less free. I did a test run and my computer is paging to swap like crazy just for importing images. I usually do RAW to DNG. Then it crashed. I'm wondering if Aperture is better? Is it better optimized for OS X? Will it use less resources for basic tasks like importing photos? If it's faster, it may be worth buying again. Obviously if Aperture is also a resource hog, I may be forced to bring my powerhouse laptop computer.