Knox, as the name suggests, allows you to create vaults to protect sensitive information. You can create as many vaults as you want, for as many needs as you have. For each vault you need to make sure you have a strong password which nobody can easily uncover.
Knox offers both 128-bit and 256-bit AES encryption, which ensure that any data you put in vaults is safe and sound.
Overall, I did find Knox pretty much similar to creating an encrypted disk image from my Mac's Utilities. Set up your vault, drag the sensitive information and close it. Then make sure you have the right password to open it up.
So what would make you go for Knox? Probably the fact that, apart from protecting data, it will allow you to make good backups and integrates well with your Mac's Spotlight.
Knox is a good one stop solution to protect and backup sensitive information.
