One thing running your own SMTP/IMAP protects you from is faceless lockouts. My partner was locked out of her Hotmail account and no matter how much evidence she provided Microsoft's shame-faced automated system refused to give her access. No court of appeal, nothing. Turns out she has an important email regarding her Indefinite Leave to Remain in the account containing a UAN she now needs access to in order to apply for a Biometric Residence Card to ensure she can continue to work in the UK. Fuck big email providers, I say. Legislation needs to be passed to make them accountable when locking-out users from their accounts.