I have used many firewalls. After changing a lot of firewalls, I have now settled on Kerio. ( I use Kerio 2.1.5, the newer versions do more harm than good ). I find it better than Zone Alarm and Outpost. Its a very good firewall. I have never had any conflicts or problems with it. It is very efficient and light on memory. Creating rules for applications is a piece of cake. The best part is that its free.