There is a big concern about the sync speed between Apple devices, I have files created in two MacBook Pro and those are not visible on either side, this is not related to the internet bandwidth I believe it is part of the synchronization process.
The product feedback indicated in another reply might not be answered because it is received and they will check without the commitment to reply personally.
The problem is having different versions of the same files in two different machines (meaning the saving is not immediate) therefore document portability is questioned, file version control is difficult to manage in those conditions.
I just created a file in Pages, saved it into the iCloud folder, and checked the sync between the devices, still cannot see in the other Mac. The concern is that how to trust where the information is.
I believe Apple saves part of the info (or a whole) in the machine and then upload it to the iCloud, the problem is how to preserve the document integrity if we are working from different machines into the same document (how to confirm the latest version), in the beginning, I believe it was related to program used (MS Word), but same is happening with native applications, therefore it is not related to differential program management.