Not sure if anyone has noticed but the Office 365 Preview Service Descriptions are published here - http://technet.microsoft.com/en-us/library/jj819284.aspx. There is really good information in here to help you evaluate all the features and capabilities that are available in each type of Office 365 plan. Remember these are Preview and subject to change; however this will really help you with your planning!!!
If you read my blog at all, you will know that I constantly talk about Service Description updates and such. These are really the most important documents customers should be reviewing as part of their decision to the cloud.