[wilsonng]

From what I remember, it appears that the APIs for iCal and Reminders doesn't have sufficient documentation to help developers get up to speed with Reminders and iCal. It has been a lot of testing, experimenting, and hair-pulling for developers to figure out what Apple's APIs are.

Other programs have also had issues with Reminders and iCal in Mountain Lion. BusyCal has had to yank some features such as syncing tasks. I tend to sync to Google calendar instead. Apple hasn't had a great track record when it comes to cloud services. MobileMe was the latest example of a major faceplant when it came to cloud syncing.

iCloud has been a moving target from the beginning. Every time Apple issues a developer release of the latest Mountain Lion builds, iCloud has somehow changed and broken something. Developers have had to create workarounds that would work in one build of OS X but not in a later build. This is the frustrating part.

iCloud had a lot of promise for syncing cloud documents. But Omnigroup and many other companies have seen its limitations. It has gotten to the point where Omnigroup will be releasing OmniPresence to allow syncing of complex documents that iCloud can't handle.

I prefer using Dropbox instead of iCloud for syncing documents across computers. iCloud is still in its formative stages and hasn't really set hold quite yet.