I was doing some stage photography for our Passion Play and I decided to take my MacBook Pro to download the cards as I went. A friend asked me why I ended up with so many shots (over 1500) from this one evening. The answer is simple: in such low light, you're working at the very edge of the capabilities of the equipment and the probability of getting it sharp in a single frame is practically zero. I like to shoot stage with little bursts of three to five shots, which usually yields one or two good frames per burst. Even if you get them all sharp, there's always the chance that someone's eyes have closed, or a hand has covered someone's face.
All that said, I am so ready to have a camera that has ISO 6400 or beyond :-)
So, Aperture. My main concern was working fast, since I didn't have anyone to empty the cards for me. I wanted the machine to ingest the images and move on, so disabled the automatic generation of previews and asked Aperture to use the embedded JPEG preview from the camera (in Preferences > Previews tab). Then I stuck Aperture on Quick Preview mode and got to work.
The process of import went very well. Unfortunately, I managed to screw up at least once, possibly twice by pulling the cards too quickly after asking Aperture to erase them. The result was some images left on the cards, which I accidentally imported again as duplicates. I had forgotten where the "Don't Import Duplicates" setting was and assumed it was on. I thought it was a preference that I had already set, but it's actually a checkbox on the import panel. Lesson learned. It was easily enough fixed by creating Smart Albums based on Import Session (thanks to Pat Berry for the idea).
The other slight wrinkle was that it was difficult to tell when Aperture had finished erasing a card. In Aperture 1.5, the project would continue to show the import progress spinner until the card was erased and ejected. As soon as you saw the project shoebox icon, you knew that the card could be yanked. I need to do a little more testing, because now I'm not sure how you know with Aperture 2 - it shows the shoebox icon as soon as it starts erasing the card, not when it finishes. That was really the reason why I ended up with partially-erased cards.
After that, the process was smooth as silk. I did a very quick reject-or-one-star pass just using these previews. I like to shoot using the Monochrome picture style on my 30D. This applies a monochrome conversion to the embedded JPEG preview, which you see on the camera's LCD. The actual RAW data is still colour, though, so you don't lose anything. What I found was that, with Aperture using the embedded preview, the image would be initially rendered in colour, then snap to black and white. This was a bit distracting for the rating step. My guess here is that Aperture was first rendering a blow-up of the thumbnail that it generated from the RAW data (in full colour), then almost immediately rendering the image's embedded B&W preview on top.
The only other problem was that the embedded JPEGs from the camera are fairly low-resolution and don't look great at full-screen on a 17" laptop. In particular, for those I shot in colour, there was significant apparent posterisation of the colours due, I suppose, to the compression applied. That's not unexpected, so the next step was to have Aperture generate proper previews for each non-reject image. That took a while, but made Quick Preview mode even more useful for the finer stages of rating.
Apart from those small wrinkles, Aperture 2 ran brilliantly. Scrolling through all those thumbnails and previews was as smooth as silk.