Good article on this topic recently appeared on MacStories
I guess what we're asking for is a file-picker implementation, not that everything else isn't already pretty flipping amazing, cuz it is.
I think we should be clear about the difference between iCloud (pre iOS8) and iCloud Drive
I would understand "iCloud" support as meaning "iCloud Drive" support since the official release of iOS8. Application's that support iCloud Drive store documents in an application specific folder, but I can browse that folder in Finder and on the Web, much as I do Dropbox folders. I can open an application's files in whatever other application can support the file format. I can save Numbers files in the "Numbers" application specific folder, or somewhere else if I want to. There might be other magic that happens by having application specific user files stored in the application specific iCloud folder but so far I have not noticed anything.
This is what I would like in Editorial. Even if there is no application specific "Editorial" folder, I would like to open and save files to iCloud Drive. I, too, use U3 and I think this is what theorginalbudman was talking about.