Knox appears to be largely aimed at frazzled IT administrators in BYOD environments. Its big selling point being that with Knox, administrators can specify which apps will or won't work. There's also a bunch of preloaded apps on Knox. as well as a growing number of apps available from the Samsung Knox App store.
IT administrators can also choose which apps can share data within Knox. Some app vendors also have special offers available for discounts on selected apps.
Switching between Knox and normal modes happens via a shortcut in the app and notification trays. The Knox shortcut is password locked.
Switching between personal mode and Knox mode on my Galaxy s4 was pretty seamless. Aside from a small lag as the switch happens, the exercise is almost instantaneous.
Data entered in any of the apps in Knox mode isn't accessible unless you're in Knox mode. For instance photos shot in Knox mode don't exist in personal mode.
Shortcuts to Knox mode apps can also be placed on the home screen in personal mode.
Tapping these fires up Knox mode. Businesses using Microsoft Exchange should also note that Exchange management policies work with Knox. This means that remote wipe commands will work with Knox.
Getting set up is dead easy. Knox compatible handsets have a shortcut so that it can downloaded and installed (it's also a freebie). Once installed, you're prompted to set password which is used to access Knox. You're also asked for a backup PIN in case (like me), you forget the password.