Informant Sync is designed to sync all features and options within the informant application for data assigned to that service. Informant sync can sync items that other services don't support. For example Google and Apple don't support checklists, icons, tags, or travel assist events. Informant sync can sync all of that.

Each event and task can only sync to one service at a time. So when you create a new event, choose a calendar that is synced with informant sync at the 'calendar' option. When you create a new task, choose a project that is synced with informant sync at the 'project' option. Each event and task will only sync to one service at a time. For example, if a Calendar and its Events sync with Google, then neither the Calendar, nor its Events, can sync with Informant Sync.  

The following is a list of all the types of data that informant sync can sync between your devices:
 
Calendars  
Contexts
Tags
Tasks
- Checklists
- Projects
Events
Triggers
- Travel Assist
Image Attachments:  Since these must be synced to/from the server during a standard sync session (rather than independently in the background), large picture files can slow down the sync operation, or cause it to timeout completely.  For this reason, it is currently not recommended that image files much larger than 2 MB are attached to events or tasks.
Smart Filters Smart Filters that have any rules which reference a Project that does not sync with Informant Sync, cannot themselves sync with Informant Sync either.
Settings Not all Informant settings or customizations are syncable.  There is no authoritative document that lists which settings are synced, and which are not.  Informant was designed to allow you to customize each device in the way you want. For example things like calendar colors or icons will sync with that item. Background colors or themes will not sync.

 For items that are listed, it can be assumed that all items related to that type of data are also synced.  For Tasks that would be things like: Locations, Alarms, Recurrence rules.  For Events that would also include Attendees.

* Contacts:  Informant does not maintain its own contact database, it simply uses the device Contacts.  It only syncs Contacts that have been configured as attachments on an Event or Task.  It does not currently sync Contacts as standalone entities so you must be able to see your contacts in the native contacts application that came with your iOS or Android device in order for informant to be able to access those.