I use the adapter with a 2006 MacBook Pro. After downloading the driver, runs smoothly. Maps are quickly identified and as a layman I can not find fault with the transmission speed. It should be noted that the reader in use is really very warm. Annoying is that when you eject the reader in my case (Mac OS X 10.6) results in a kernel panic and the computer crashes. Even when the pressure point of the SD card ejection and the Express Card ejection are other I did this happen several times.