One of the precipitating events for my decision to migrate from Google Apps to Office 365 was Google's decision to restrict Exchange ActiveSync (EAS) support to paying customers. This rubbed a lot of people the wrong way. The alternatives Google suggests -- IMAP, CalDAV and CardDAV -- are not only harder to configure, but they don't work all that well. Google's CalDAV implementation, for example, doesn't let you invite another user to a calendar event.
Even the fact that I was a paying customer didn't stop me from being affected -- Microsoft changed the Windows 8/RT Mail, Calendar and Contacts apps to blacklist all Google users from EAS access. Microsoft provides alternative means for syncing email and contacts to Windows 8/RT. For Calendar, Microsoft's official advice is to use Outlook.com instead.
Both Google and Microsoft came across as petty and unhelpful in this episode -- but I wasn't prepared to dump both of them. I decided I wanted to have EAS support and Office 365 was the way to get it. Since I set up Office 365, I have connected from Windows 7 and 8, Windows Phone, an iPad and iPhone, Android 2.3 and 4.2 phones and an Android 4.1 tablet. No problems.
There was an unexpected bonus: EAS provides some basic mobile device management (MDM) tools and Office 365 lets you use them. You can make users set complex passcodes, force a device wipe after a set number of failed attempts to connect, and use other measures to improve security. These are the kinds of security features users love to hate, but short of a full-blown MDM product subscription this can do some good. (To be fair, Google Apps lets administrators remotely wipe devices that have been connected through EAS.)