I do plenty of real work on computers, I own a computer repair shop and clean hundreds of infected machines a month, and I will totally disagree with you.
If a computer has been in the shop for a virus, it is likely to come back into the shop for a virus unless you educate the person about safe browsing. Viruses are designed to, and are very effective at disabling and getting around all AV programs. I've seen every AV program you have listed come into the shop totally disabled by a virus.
Stupidity is stupidity, and no AV is going to protect against it. It is likely that you see so many machines come back with MSE because that is all the guy used, and he never educated the user about safe browsing. He just cleaned the machine, slapped MSE on it, and sent it back out the door. If he had used Avast exclusively you'd be seeing machines coming back with Avast.
Personally, I use MSE with great success, and have very few repeat customers. I've also began installing MSE on both my personal and customer's servers because it is probably the only good free AV that will run on Windows Servers(bet most people didn't know it works on Windows Server).
Then i dont know what to say...you have different viruses then we do other here?
Good luck teaching ignorant people how to browse, they might stand there making you think there listening, but in reality there not, they might take in 10% otherwise they don't care, they just want to get back home and get on Facebook, porn site, whatever, its true, sad to say.
I totally agree that viruses are made to disable the AV and then flood the PC with problems, and what OS is targeted more then any other? and then this said company then decides to make a AV?
Come on, what do you think is going through the minds of people that make the viruses hmmm? its not rocket science.
I have seen MSE and Trend Micro been disabled, i haven't had any of my machines back that have had Avast or Kaspersky that has been disabled by a viruses yet, Time will tell i guess? The only machine i got called back to was one that the user has not updated the AV and the firewall was disabled, Avast was still working, but was not disabled.
I agree stupidity is stupidity and thats very true, i just try to minimize the problem from what i have seen and learnt personally with all types of machines coming back (mostly XP or Vista) This would be correct, this seems to be all the other guy used, my guess he read reviews and thought ok yep it seems good use it, its free after all? and then i took over and all im getting is his machines with viruses flooded through them because MSE isnt doing the job and i also know that it isnt if i can then run Avast on the same machine and find 10 different viruses when MSE said the system was clean? speaks for its self right there.
This is where i have to totally disagree with you sorry, i have had nothing but customers coming in with viruses and its either Norton, AVG or MSE on there computer that hasn't been doing a good enough job of stopping viruses ( and yes there up to date). You say you get repeat customers? i think that just proved my point, if your getting repeat customers its not doing a good enough job, i haven't had any yet, not to gloat but its true. Im sure it will happen, just hasnt happened yet, time will tell.
Fair enough on windows server, i didn't know that either but i run Linux based servers so i don't have to worry as much i guess?
All in all its better to have one then none at all, all are going to protect to a agree right? some have different taste then others because of personal reasons etc, and im the same, i have personally found MSE to be "ok" but just not as good as others, so i personally stick with Avast for a free AV and Comodo for a free firewall with great success.
) All in all, AV is a fallback.
I cant charge that much, for a viruses clean and a general clean up its $110 ($55 US 
im just pricing to what everyone else charges. Im moving to the US in that case 