What article are you referring to ?
Don't believe RAID of any sort is warranted or a good return on investment for 99.9% of all PC users. A second hard disk drive and some good backup or imaging software is a much simpler and cleaner solution and doesn't not require matching HDDs, doesn't require a RAID 5 controller nor require idle spare hard disks.
Your article about adding two drives to your computer in Raid 1 configuration should have mentioned that there is an even better way to go if you add three drives.
A three drive system can use the much more powerful Raid 5, which would give much higher throughput, twice the storage (2x not 3x) and the same level of security. Just like Raid 1, a failed hard drive will still allow the system to go on working - although a little slower - and can be restored to full health by the simple process of replacing the failed drive. You don't even have to worry about restoring the data to the replacement drive, the system will do it automatically.
The only caveat is that when you buy the three drives, you should really buy a forth to sit unused until a drive fails. This is because if a drive fails several years later, you will be unable to purchase the same drive as a replacement and Raid systems expect all drives to be identical.