I don't think this is all that different from Dropbox. For years, Dropbox was able to outperform all the big players who tried to compete because their core sync technology was rock-solid.

Still to this day, I find my ICloud sync folders can be fairly unreliable (files will take a mysteriously long time to appear once in a while) - I've never had anything like that sort of an issue with Dropbox (although I haven't used it in a while).