Here are my thoughts ...
There are a number of things "backing" up needs to do :
1) Protect from file corruption
2) Protect from accidental deletion
3) Protect from hardware failure
4) Protect from theft
5) Protect from your house burning to the ground or other acts of God
Any solution that sits in your house will only cover 1, 2 and possibly 3.
To cover 4 & 5 you need an off-site backup.
Personally I hold everything on a single 1TB drive inside my PC. I then sync these files to two other 1TB drives. One of these is in my desk drawer and the other one is 4 miles away. Every month I swap them over.
I also write my photos and website stuff to DVD-R every year and keep them off-site.
For syncing files I use a paid for version of
Allway Sync. I previously used
Microsoft Sync Toy but that struggled with 800GB!
The whole lot is encrypted with
Truecrypt. This means if anything is stolen the data is safe. They don't get my media collection, photos, personal data or even a bootable computer. They get the hardware which they will struggle to sell because it will appear to be broken.
This may all seem paranoid but I've seen people lose their entire family photo collection because their "backup" was a folder on the same drive as the originals. Not much use when the hard drive fails.
I tend to prefer old fashioned copying files onto media rather than using a "system in a box" because recovering the files doesn't involve the "system in a box" working. I can read my backups on any PC using multiple operating systems.
So the Apple device looks nice but I would still supplement it with some sort of offsite solution as well. At the very least protect the irreplaceable stuff. Films and MP3s can be replaced. Photos can't.
