Well, it is not me saying that, it is actually Clint Boulton, eWeek. He published an article on 10 Reasons Why Google Won't Beat Microsoft in Cloud Collaboration and they are:
I do not agree with all the points but what is really interesting to me is that he does not really talk about security. I am convinced that there have to be a few areas where the solutions of the different cloud providers have to be compared like the security and transparency of the the way the Cloud is run (e.g. we are ISO 27001 certified), the ability to federate the identities from on-premise to the Cloud (ask your provider), monitoring and management from the client to the server on premise to the cloud…
I am convinced that this discussion will change fairly soon as well!
Roger