How the Apple iCloud compares to Google's cloud - Computerworld:
That enables a lot of app-specific features to be universally applied. Since Apple is making the APIs for iCloud storage and sync available to all its developers, it should offer an impressive editing experience from iPhone to iPad to Mac or PC and back (assuming the app has a Mac/Windows counterpart). It should allow data and document access to be seamless. And with the sync capabilities of iCloud baked in, it should also be effortless ; there's no need to move a file using some other app or a clunky Web-based upload form.
On the other hand, your actual access to documents becomes more limited. You need to have specific apps on each device and you need to access your stored documents using Apple's solutions. In other words, it's a more closed system.