In answer to your question of how someone decides which Anti-Malware software to use, it comes down to experience for me. Keep in mind that I, thankfully, haven't had to clean a computer in the past year. Also, please keep in mind that this is my personal process. I'm not looking to argue about it because you aren't going to change my ways, but I figured you deserved an answer as to the thought process I use.
When I did clean computers on a regular basis, my process was something like this...
Use the program that worked "best" last time (For example's sake lets say it was Ad-Aware). If it fixes the problem, great... its my goto for next time, if not, roll to another program that I've had success with in the past (e.g. Spybot). If choice two doesn't fix the problem I go down the list with other programs I've used before, then move on to ones I find from sources that I consider reputable (anandtech's Security section for instance).
Whichever program fixes my problem, unless its some one off solution from Symantec or something that is designed solely to fix that particular problem, will take the place in my mind of "best". Then, when I see a post in AT-Security asking "Plz hlp!!!!1111 Mlwr stps vwl kys" I'll recommend that "best" program (the word of mouth aspect of things).
I would assume that I'm not the only one that uses this process, and at some point many folks found Spybot or MBAM to fix a problem that Ad-Aware missed. And in the future Spybot/MBAM fixed another problem before they moved down the list to Ad-Aware which further cements the idea of Ad-Aware being an unnecessary product.
I'm also the type of person that frequents a few tech forums regularly and I have a general idea of which people know their shit enough for me to take advice from. I'll take the advice of someone that I "know" over some testing organization regardless of their credentials. I'll reiterate the previous comment that I just assume any organization's test results or reviews have been bought and paid for. Call me jaded, but I have more faith in my fellow ATers to help me choose good software than The ACRONYM Foundation.
The fact that two proven solutions (Spybot and MBAM) are absent for the previously mentioned test seriously puts a damper on their validity in my eyes. Regardless of the actual process or testing criteria that may have lead to these programs not being included, I won't even give it a second glance once I see some of my favorites absent. I can appreciate that they don't include themselves, possibly because they have a more specific scope than some of the other solutions, but that doesn't change the fact that I will disregard the test outright as soon as I see them missing.
Keep in mind that you are asking these questions on a tech forum, so our responses likely aren't the same as you would receive from folks that aren't technically inclined (they are probably asking "us" for advice anyways though ). I'm sure there are some people that will read the virus reviews, but I would wager that more people make their decisions based off of prior experience, a process similar to mine, or asking someone that made a decision based off of prior experience.
This could also be a part of the problem...
Google Search: best anti-malware software free
In addition to appearing first on the list, MBAM is mentioned 4 times on this page to Ad-Aware's 2. Also... whats not on the first page at all?
www.virusbtn.com
Googling "anti-malware comparison" also doesn't bring you any results for virusbtn. (Am I the only one that reads that as "Virus Button?" lol).
In fact, the last time I tried finding anti-malware comparisons that were at all reputable it took me at least an hour of digging... and the only reason I put that much effort into it was to prove a point to someone about the efficacy of using anti-malware products. Anyone that is just trying to fix a problem likely won't spend that much time researching what product has the best detection rates... the time spent looking could have been better used actually running a scan.
I also did a google search for
anti-virus comparison. Again, no mention of the Virus Button, but there is a legitimate looking (I'm taking it at face value here, and not actually digging because I'm tired, but .org in the URL screams "legit" to a lot of people) site as the first result:
http://www.av-comparatives.org/
Ad-Aware is absent from this list, as is Spybot and MBAM, but if you are trying to get your product out there you might consider having a focus group (not tech people, we'd likely skew the results) do google searches and see what actually comes up. Its all well and good that Ad-Aware scores well on Virus Button, but if no one can find it then its a waste of effort.
Things get even worse when you actually take a look at the Virus Button results. Its either a pass or fail... and I'm not about to spend $20 just to see some detailed test results. Also, some users may be looking for Windows Vista AV/AM comparisons and will completely disregard results for Windows 2003, so Virus Button is completely irrelevant to me as a consumer on multiple fronts.
Please keep in mind that I have no intention of sounding harsh and that tone does not translate well through text. I'd like to reiterate that this is the process that
I use when dealing with malware (and virus for that matter) problems and how
I see the Virus Button results. And sorry to keep calling it Virus Button... it just makes me giggle. Also, disregard bad spelling and grammar... I've been up for damn near 36 hours which could also contribute to how long this post ended up being.