Ive used Kerio4 for about a year and did all its possible upgrades, but I think they didn't fix "everything". Using opera 7.23, Kerio still allows some website imbeded ads to appear (although its pop-up blocker is quite good). Now, im using Zone Alarm Pro and to my surprise Zone Alarm detected some intrusions which Kerio4 didn't. Well Kerio is still a very solid firewall although configuring it "properly" is a real pain on the head.