If you have some knowledge of SQL, you could do some direct queries of the ePO database and put the results in Excel, Access, etc. Figuring out the tables and relationships can be a bit of a pain, however, because there isn't any documentation available from McAfee.
Ok - I will share some insights at my own risk I don´t know if this is "official" knowledge - at least the feature is not supported in any way until now. If someone at McAfee feels offended please feel free to delete my post.
Here is a way to compare policies inside ePO:
1) Open the ePO 4.6 GUI
2) Open the following URL once: https://myeposerver:8443/PolicyMgmt/comparePolicies.do (replace servername and port with your configuration)
Afterwards you will get a new menu entry "Policies -> Policy comparison".
Then select the policies which should be compared. All different settings will be marked yellow.
PS: I don´t know if this will work with ePO 4.5
Thanks metalhead for the suggestion, no love for this from ePO 4.5. "An unexpected errror occured"