I have been running MBAM (free version, scan only)/MSE for years without ANY issues, not a single virus on any of my windows machine.

I can't understand the need for bloatware aka "anti-virus", if you take the time to educate the users and train him to stop clicking and installing whatever pops up in their screen then they can pretty much rely on MSE and have a clear mind.

Obviously MSE might not detect EVERYTHING but basic education on how to treat spam/advertisement/phishing goes a long way.