If you have event handler activated in the target SharePoint you may see few issues with the files (unable to open files, missing metadata) after migration. Then in that case you need to deactivate the event handler and migrate it again and activate it later after migration.

Also SharePoint caches user credentials which may lead to impersonation issue which may fails to upload document in target SharePoint using Tzunami. So in order avoid this it is recommended that you use the same farm administrator account to run the remote service. Using different account may create multiple issues if you have event handler activated in your target SharePoint.