Most of CreOFF's administration (e-mail, calendar,...) has been migrated to Google Apps for Business, running on Google's cloud infrastructure.
What are the benefits for CreOFF?
It takes an effort (and some risk) to move all your sensitive data and e-mails to a different infrastructure. Still, these features persuaded me:
Not just an e-mail service, but also texts, presentations, spreadsheets, private wiki/sites can be shared and worked on simultaneously by several people (worldwide if necessary). Some of the Google Wave technology was implemented into Google docs nicely.
Data is moved into the cloud instead of one single pc: access your data from any pc or mobile device, worldwide. Google offers reliable and redundant data centers, faster worldwide access.
Lots of storage space
Every mailbox gets 25 Gb of storage space. Hmm... that will keep me happy for a few years.
The migration of all CreOFF's mail accounts to Google seemed like the biggest challenge, but luckily Google provides several migration tools which make the job simpler. The move from IMAP server to Google Mail was done in one afternoon, and even an unforeseen problem with our creoff.net domain was handled promptly by the Google Apps support team.
...one less (mail)server to maintain and troubleshoot.
There's a FREE version available, business edition costs 50$/user. Read more at the Google Apps site.