MBAM isn't an antivirus program........
And yet somehow it is far, far superior to antivirus programs.
One computer I recently cleaned up, I set the antivirus software to scan (forget if this one was Norton or MSE) along with MBAM concurrently. Malwarebytes found everything that the antivirus found, plus it found a couple dozen more things that the AV software did not.
I've just been so frustrated with antivirus software. My basic routine for cleaning up a bad system, first step is uninstall whatever AV software is on the machine, run tdsskiller, combofix, malwarebytes, & hijackthis. After all of that I then reinstall the AV software, and it still detects nothing like it detected nothing wrong when I began the cleanup process.
I don't know, just my rant against the ineffectiveness of antivirus software against a massively wide range of crap that every other good cleanup software finds and deletes off.