Steve Jobs liked claiming that Microsoft merely copied what Apple did... it turns out that Apple has copied Microsoft this time.
Microsoft Exchange is one of the best database servers you'll ever use. You can make offline changes on multiple devices, and it will handle things automatically. It just works.
iCloud is what happens when Apple decides to copy Microsoft Exchange, and possibly Sharepoint.
iCloud is NOT something that lets you see your calendar everywhere (unless it's the iCloud calendar).
iCloud does NOT sync your settings across devices
iCloud does NOTHING to help you deal with an Exchange account you want to see on all your iDevices.
$218 down the drain....