I'd also be interested in hearing anyone's experience with SD cards. I already had a 32GB class 4 card, so I have it in my 13" MBA right now and am copying about 10,000 files (28GB) of photos from an external USB drive. It's taking forever, looks like it will be about 6 hours. Copying from an external USB drive to the SSD is MUCH faster.
I wonder, is the card slot actually connected to the USB bus inside the computer, or does it have some kind of dedicated connection? Will do some testing once I've got all my files moved over. Yes Newfiebill, I completely agree with you! The protruding SD card is probably my only complaint about the MBA hardware.