Here’s a handy site that allows you to quickly compare the features across Office 365 plans. You’ll find it at:
http://technet.microsoft.com/en-us/office365/fp123607#!
Simply select the options that you want at the top, then the service and finally the plan. The resulting list below will list all the features and whether they are available in your selection.
Pretty handy eh? And you know what? I can see it is all built using SharePoint lists. Even cooler!