Calendar / Contact integration with Android

Calendar / Contact integration with Android

Hi. Could someone confirm my understanding of the current options for integrating calendars & contacts with Android.

1. The Zoho Mail app is a stand alone app proving no integration with Android.

2. ActiveSync provides integration for both but has numerous limitations such as:
    Only supporting one calendar.
    Not supporting contact groups.

3. CalDAV Sync provides integration for all calendars on a per calendar basis.

Is there a fully functional alternative that I'm not aware of? Cheers.