> Also, email is a critical service, something where I don't want to have to deal with downtime, especially if I'm away traveling or something like that.

I have to say that as the most critical service of all, that's one of the reasons I do host email myself!

I can't and won't take the risk of being locked out by the whims of some third party misconfiguration (we've all surely seen the endless stream of misfortunes by those getting locked out of gmail/etc).