A few days ago i picked up a My Book Essential Edition 500gb to use with Time Machine, and so far it is an amazing external HDD. The My Book backs up quickly with usb 2.0 and has a whisper quite fan. One of the features that i like is that its plug and play all you do is plug it in and it powers on and off. In Mac OS X it immediately popped up on my desktop when plugged in and asked if wanted to use it as my Time Machine back of drive, no drivers or install was needed. If your looking for an external HDD for time machine i highly recommend this product for both its great features and low price.