I use Avast IS and IMHO it has a very good decent firewall which is very user friendly and highly configurable. They haven't fully implemented the Agnitum firewall module in their suite yet. When they do their firewall will get better hopefully.
I used Avast Security Suite for 3 months I got a 90 day free trial.
The firewall is more easy to configure outbound and inbound network traffic compared to Windows Firewall with Advanced Security. Of coarse you can do the same with Windows Firewall it just takes more work. The effectiveness will be the same. Once they implement Agnitum Outpost in their firewall it could be much better, since Outpost has always had excellent network control.
I have always preferred ZoneAlarm Free since it has Application Control center for fine tweaking network control.