>But I have no idea what the migration of a decade of email across 5 inboxes will look like; not to mention Calendar and contacts.

Painful. I know first hand. It is no surprise that these companies make migrating out of their services as painful as possible. This is why I treat personal services like I treat business services now: if there isn't a realistic exit option, I don't use it. There are just too many examples of services being cancelled, accounts banned, and prices jacked up unreasonably.