Information Foundation Mail Security For MSE vs Symantec Mail Security for Microsoft Exchange

Greetings,

I'm a bit of a newbie here, but I was wondering if someone could recommend/explain the difference between Information Foundation Mail Security For MSE and Symantec Mail Security for Microsoft Exchange.  I am running Symantic Protection Suite Small Business Edition 4.0 on Windows SBS 2011, and was wondering what's the best option. 

Any help would be greatly appreciated.