Firstly, this is the image processed by Aperture 1.5.4 using version 1.1 of their RAW decoder. It's OK, but there's a significant and nasty yellow band around the sun - a hard step transition between highlights and white.
Aperture RAW Decode 1.1
A while later, I reprocessed this image in Adobe Camera RAW and Photoshop CS3. This gave a much better result in the bright highlights around the sun. This image has a slightly different crop, but only in the shadows.
Adobe Camera RAW
Last night, I reprocessed the image again in Aperture 2 using the RAW 2.0 decoder. I think the results are now practically indistinguishable from ACR. They're possibly even better.
Aperture 2, RAW Decode 2.0
So far, I'm very impressed with the new RAW decoder in Aperture 2.