ISO 27001 Security Concerns

We are investigating the usage of commodity offering like Google Apps
in our organization. The protection of the data and intellectual
property is a concern as well as about the maturity of the offering.
I am wondering if somebody has evaluated or understood related
security, data confidentaility risks and legal implications.

What, according to you, are the most significant risks of deploying
cloud in your organization?

Any support, recommendation or lessons learned would be helpful.
Thanks in advance