About the testing, I was speaking of the comparison tests run by sites that claim one product is better than another.
Those kinds of test are run on clean systems with the default settings. They may not always be the best settings or conditions to accurately test the product.
For instance, I have a lot of experience with ZoneAlarm, both in the practical live use, and in testing. I have run beta testing, Alpha Testing, and testing on fixes. I have also run the tests that various sites use to see how well the product works. The installs always go well on a pristine system, but once you put it on an active used system, things can go wrong. The reason is that the writers cannot take into account every piece of software out there. They cause conflicts or create unexpected holes.
As for the product testing itself, I have been able to duplicate the results on a brand new install with all the default settings. But with only the basic changes in configuration, that the average user using the product would do, the results of the testing sites are blown away.
When you get right down to it, there is not a single product out there that is 100% effective. This includes all the AV and firewall products. I am talking real world effectiveness. People change settings to customize it to their system and software.
The BEST security software that you can use, is the one that you install and run all the time. That works so well with your habits and software that you never turn it off because it is interfering.
What most people forget is that security software is only a secondary defense. Your primary defense is behind the keyboard. If you persist in frequenting questionable sites, and downloading hacked software, you will get infected. No scanner of filter will be able to protect you.
But if you only go to sites that are on the up and up, and download software from reputable sites, then chances are your virus scanner and firewall will not get that big a work out. To prove this point, I actually surfed the web for a week with all my security turned off. I never got infected by anything worse than a tracking cookie. I don't recommend that, I was walking on pins and needles the entire time and it is risky.
As in all human endeavors, the key to safety is about 6 inches behind your eyes.