For a couple years, Malwarebytes was the only software that would detect and remove certain kinds of malware, like rogue spywares that were coming out of Russia. I recall for one summer, I think I was the only guy in the small town of Pueblo, Colorado that knew how to remove it. I made a killing. It was easy, try a system restore and if that didn't work, Malwarebytes and a virus scan. It was small, light, easy to install, and effective.
However, lately they've been bloating
I think they're trying to get into the antivirus market and they're offering their free version as a beta test for big future plans.
Comodo gives false positives because it's still slightly unbaked. But I have every confidence they'll end up with a product as effective as their firewall.