Office 365 is compelling in several ways and it wins hands down in one specific situation; where you're not putting everything into the cloud and you already have Microsoft IT in your business. I've also been thinking about the implications of this hybrid approach.
Lead on cloud - or the business will work around you: my view on why Microsoft's view of the cloud is one of the more pragmatic approaches, written to accompany my interview with Kenon Owens about System Center 2012 where we decide "IT departments can't ignore the cloud. If they fail to deliver systems that are fast and easy to set up, business teams will just sidestep them and sign up for a cloud service — whatever the consequences for security or compliance".
Talking to Microsoft execs about that view of cloud, I got a nugget about the way Microsoft runs the business that I hadn't known before. Microsoft execs: paid by results