Spinning up a new instance of Office 365 to provide email for a brand new domain is easy; migrating email from other domains is not. If you are a systems administrator who can count to 10 more or less accurately you are probably ready to dive in but the everyday user may find it a bit of a struggle. Let's take a look at the …
I have a bad feeling about this...
All very well & good, but many people will be running legacy systems that even originally bore about as much relation to MS best practice as David Cameron bears to the word talented.. and will probably go down more times than a Clinton intern. Have you got any good related disaster recovery-recovery info regarding this procedure if it all goes Welsh NHS?
Have you got any network load figures on the different methods - cos I have images of networks going completely Gormless George even if its done without users printing their CV & downloading last weeks Game of Genetic Sexual Attraction (except near Lord Carey).
Outlook != IMAP client
"My quixotic struggle to get Outlook 2003 and Gmail to cooperate in a friendly fashion serves me as a daily reminder of that."
Outlook, from all years, is a terrible non-compliant IMAP client. That shouldn't surprise though, because Exchange is a terrible non-compliant IMAP server.
When I last dealt with Exchange at any scale the officially recommended solutions to allow non-Windows systems to access Exchange were: terminal services (seriously!), Entourage or webmail (from non-IE browsers). IMAP has always been an afterthought in Outlook/Exchange. We made do with IMAP access for a couple of years but then moved on because it was so terrible.