Kerio is good but since it's a rules based firewall the user should learn about how to set up rules to secure their pc and not go with just the default configuration. Not as simple as Zone Alarm but a good learning experience for those who are so inclined. (Also, the Kerio people used to be associated with the old Tiny Personal Firewall. Not associated with ZA as far as I know. I recall when the split happened with Tiny and some of the Tiny developers released Kerio.)