RAID is the technology most used to ensure data is not lost from Hard Disk Failure.
Backup Software that keeps dated versions of files is most often used to ensure files are stored on separate media from the original location and can be recovered if you have a "WOOPS" moment. That is if you deleted or corrupted your latest version of the file.
Hardware RAID 1 (Disk Mirroring) is great, simple, flexible, and transportable. If the master disk is your system disk - you can boot from the duplicated disk!
(See Digitimes Press Release)
You Need BOTH. Recovering a system from backups and reinstalling software is a time consuming task. It can take days.
Run a RAID system if you can.
RAID 1 is simple disk mirroring. You get 2 current copies of all files. However if you delete 1 you delete both - so it only protects from drive failure - not WOOPS.
However, using more drives and swapping them periodically means you have a place to go to recover that file.
Running RAID does not prevent you from running other backup software and - you should run other software. Certainly have a software backup schedule of your key document directories on a daily basis and have the software rotate around 7 or 30 days.
With our ARAID 5000 the disks mirror without keeping setup data on the disk so you can use either working disk as master or slave and you can use them immediately external to the RAID unit. I use the ARAID units to copy my disks external to the system - with just power connected - and then reinstall the source disk in my laptop. Simple disk duplication but you may need to consider your laptop warranty with this approach.
Anyhow - see our videos on the matter at the links below. Yes we have been doing it a long time and the new ARAID 5000 is SATA3 speed.