I have not migrated yet, but here are the facts based on a long back and forth with Salesforce Support planning to switch from Salesforce for Outlook plugin to Outlook Integration + Einstein Activity Capture (EAC). I hope this helps because EAC sounds nice but it comes across as being half brain-dead and there is a sore lack of documentation. Even Support had to come back a few times with answers. That said, there is a way to do everything except automatic upload of emails into Salesforce.
EAC has two components: Capture and Sync.
Capture: Automatically uploads activities and email into Amazon Web Services storage. You cannot access it (there is no API for it). It appears magically in the timeline in Lightning. When you turn on EAC it automatically loads the past data (I think 6 months worth but you can check.) The storage is limited to 3-6 months for free version, or EAC Standard lets you do 2 to 5 years. The data stored in AWS disappears from the timeline when this period runs out. (it hangs on a bit longer for use in machine learning models but you cannot access it.)
Sync means that activities are uploaded to Salesforce and stored in Salesforce like ordinary activities, so they do not disappear after time like the data stored in AWS. Email cannot be syncd.
For us, we have strict compliance rules so this whole scheme is a major hassle. Users need to manually upload email into Salesforce using the button in the Outlook sidebar provided by the Outlook Integration system. We are worried that if they see email magically populated in the timeline they will think they do not have to upload it, but they will be wrong because the email will disappear after 6 months if you can imagine that.
It is possible to purchase just one EAC Standard user account and then all users can get the 5 year AWS storage. For us, that might be useful day to day but actually the data in AWS cannot be deleted or downloaded, and cannot be reported on in Salesforce because it is not in Salesforce. It also would not show up in a custom lightning web component I created that shows all activities and meeting notes in one place. Also, by the way when you use EAC you cannot use the activities list views in the related tab I think. Oh, and EAC will not show attachments from Outlook. So it is really dumb. Maybe that's why they extended the Salesforce for Outlook deadline into next year?
The solution I got accepted is:
- Install Outlook Integration to get the sidebar and manual email upload button
- Get EAC free since we have <100 users. Use Sync to automatically upload activities into Salesforce, but do not Sync email.
If anybody has conflicting information please post it, thanks.