Sounds like I'll have to check out Fastmail :-) However, please bear in mind that if you've got to switch over a whole organisation, you'll have to keep UI friction to a minimum. Users who have used Gmail for almost a decade (our Outlook, for that matter) will be extremely hesitant to be dragged over on to a new service. I guess, a fully featured mail server doing all the work in the background while offering you a front and that looks like OWA, Gmail or $UI would be ideal (pipe-dream, I know, but wouldn't it be great?). Still, I get what you're saying and I'll look into it. Do you have any experience with Fastmail for business? Can it be branded and used with different domains and aliases without paying through the nose?