Most flash drives aren't going to hold the amount of data I've got backing up. (50-80 GB) Which is why I use the USB disk. And flash drives can go dead, just like any other device. So it's still a good idea to make sure you've got some kind of backup. Never a good idea to rely on one type of media. I use both flash drives, as well as spinning disks. Used to also burn CDs, but with this volume of data that's unweildy and unless I'm going to spend the cash on a blue ray burner, even DVDs aren't much better. Though for bare minimum of writing stuff, it's probably still worth it.