I do a lot of photography, and I had a FireWire 800 Compact Flash reader from Lexar. I was only able to use the thing on my Thunderbolt display with my previous gen MBA, but when I got this one I figured better to get a USB 3.0 reader than fool around with the Thunderbolt to FW800 adapter that hasn't even been released yet. So I sold the old reader and purchased a Lexar USB 3.0 CF & SD reader. Lexar's FAQ page specifically said the reader works with the Mac. Except it doesn't work with the new ones via USB 3.0 apparently. I called their tech support and they acknowledged compatibility problems with the new Macs. Annoying that they didn't post that on their website. Lexar tech support said they are working with Apple on a fix, not sure what they're working on but he had no ETA on when or if the problem would ever be resolved. Next up I'm going to try my luck with a SanDisk USB 3.0 reader.