I've tried AVG and ANTIVIR as freeware protection. This program seems to give you a higher degree of protection, but involves a little more interaction with the extra protection. For example, on occasion a program install will not work properly, and I have become accustomed to immediately going to Comodo to see if it is blocking the install.
The difference is Comodo will tend to disallow things by default, where other programs allow by default. If you want the extra default protection, a fantastic freeware choice.
License: Free Details...