Compare iCloud Drive to Dropbox or Box - password protection?

[iMore Question]

OK - I like Dropbox and am considering Box - because they permit to throw a document or video or whatever into a folder and then share just that one thing. I can also password protect or make it streaming only - but I have to have paid versions for those settings...
I don't want to pay for BOTH Dropbox AND iCloud Drive - but I don't see that Apple is making any tweaking available to lock down a shared file. Do you have any thoughts on this or can someone point me to a comparison article for further reading?

 

[Just_Me_D]

What do you mean when you say tweaking to lockdown a shared file? Can you not un-share a file?