Horrible, slow sync. Why does it need to sync what should be local data on device. Should only update meta data whether new or deleted data. Yet it seems to always need to pull all data from cloud, creates poor sluggish performance. App crashes when responding or forwarding emails. Repeated mail notifications from already notified emails. I pay for business level subscription and it's a joke being forced to migrate into the cloud and pay a lifetime of subscription, because that's the new world.