Dont really care about the entreprise use of Knox. For personal, Knox is used in Secure Folder capability in Galaxy. Secure Folder, imo is a security measure that trumps Iphone. Secure Folder gives me an environment (phone-in-phone) in which I isolate my most critical apps/accounts/data (like banking apps) of which security is very important to me. I am pretty sure this environment is isolated and secured from all the hundreds of apps I have in the phone (off which some maybe info stealing or potential malware apps).
Iphone security maybe good but all your critical apps/accounts/data are lumped together with all your other games/typical apps. If you inadvertantly install an info-stealing app (like facebook

), all your security control goes down the drain. It doesnt matter how good iphone security protects you from outside but most users will at one time or other unknowingly open the door wide and let some of these NSFW apps in. Like it or not users keep installing apps in iphone as times goes by. Some apps will ask for location/contact/other critical info access and users will typically give those permissions as they want to continue to use that app.
That's why I really like Secure Folder capability in Galaxy. It gives me a isolated secured virtual phone embedded into my current phone. I can do whatever with my phone without worry knowing my critical stuff is protected in Secure Folder Knox.