Seeing this thread prompted me to sign up - I've been procrastinating over ditching gmail and consolidating on one IMAP provider for ages.

I shelved my one main doubt (I don't think much of Roundcube) and started the process today. Seems like you've done a really good job. Recipients have been getting all my emails, and I have found the integrated migration tool invaluable in getting set up.

Good luck with the venture.