This is pretty cool. Given how many developers are somewhat unhappy with iCloud's reliability and what not it'll at least provide another choice. Might even spur Apple to try and make it work better than it currently does.
Very cool! Dropbox still sorely needs event driven webhooks or a stream of sorts. Their /delta is solid but requires an insane amount of data to catch up if I just want notifications of recent changes.
This is, hopefully, an example of how thin client devices will eventually take over. I am writing this from a Chromebook, which I love but unfortunately is hamstrung by the fact that wireless internet is not yet 100% reliable. Once we guarantee that we will have internet nearly everywhere and with a reasonable price tag/battery effect, all files will be accessed through APIs like this one.
iCloud offers one benefit over this, which is iCloud allows record-level syncing (for SQLite databases using CoreData).
Dropbox is file-level syncing. So if you have a database app managing many records in tables, Dropbox will sync the entire database when even a single record changes. iCloud would only sync the record(s) than changed.
