One thing that I've learned as an amateur tester is that testing is not as simple as double clicking an installer, waiting for it to update, and then starting to run malware.
A lot of AVs act strangely after install even if they claim they don't need a reboot. Some have settings that experienced users know they should turn on (like ESET'S deep heuristics engine or SEP'S SONAR sensitivity settings). And others have this kind of licensing based behavior. F-Secure used to have this unintuitive behavior where files that were already present on the system were treated less suspiciously by their non signatures engines compared to files that came from a browser or external drive so the manner in which malware samples were introduced matters.
I usually try to use the software for a while and become familiar before I'm willing to report on test results with them, so that's mainly why when someone asks "hey why don't you test XXXX", I would really like to but it'll take me some time to find a machine where I want to use that AV for a while to become familiar with its behavior.