"Aperture, D7000 Raw, import preview looks better than post-import"
When I import raw photos, each photo looks better in the preview in the Import window than after it is imported. After importing, when I first view the image in the Viewer, there's a moment when the photo is loading and it looks like the import preview. Then the photo changes - it loses details, especially in the shadows and sometimes in the highlights.
#1. "RE: Aperture, D7000 Raw, import preview looks better than post-import" In response to Reply # 0
Are you shooting RAW or JPEG? What you see on the import preview should match the jpeg image generated in-camera -- the camera does this even when you are recording RAW files, otherwise you wouldn't be able to see anything on the camera monitor. The properties of the image displayed on the camera monitor are controlled by the Picture Control settings you have selected in-camera.
I see the same thing that you do when importing images from both my D90 and D7100 into Aperture. I shoot RAW only, and my understanding of what is going on is that Aperture initially displays the embedded in-camera JPEG image and then "replaces" it with the product of Aperture's RAW conversion engine. RAW files converted by Aperture are typically flat and soft -- that's why they need post processing.
One way to get around this is to develop a custom preset that applies a set of canned image adjustments to the converted RAW images. You can also import presets that others have made -- I was able to get (can't remember where now) presets that emulated the Nikon Picture Control settings of the D90. In Aperture 3.4 there is also the "magic wand" (Auto Enhance) button at the top right corner of the Adjustments panel, just below the histogram. This applies some mystical adjustment algorithm based on Aperture's analysis of the image and imposes a set of Adjustments. Occasionally I find this a good place to begin tweaking a RAW file if I'm not already sure what it needs.
All of this assumes that you are shooting RAW files. If you see this behavior upon importing JPEG images then I have no clue what's happening, because in the absence of RAW processing within Aperture there should be no change....