I've worked with iCloud in conjunction with Core Data. It's as broken as the article describes, and in fact has gotten worse over time. No one really fully knows WTF is going with iCloud - documentation is basically nonexistent, support unavailable, implementation broken in trivial ways, and error messages inscrutable. I was at an Mac/iOS conference recently where the Core Data iCloud talk morphed from a standard tal…
Apple has a long story of half-finished features they try to force onto developers and users. And if that doesn't work the technology gets killed off.
The only downside of not using shiny but questionable new features is that your app won't get featured in the App Store.