none of my own personal system use any kind of antivirus other than Windows Defender or Security Essentials since I build my own desktop, simply because I know those AV themselves can cause troubles just like how McAfee always wreak havoc on my work laptop's networking and Norton's notoriously bad resource hogging, holes in AVG, Avast's resource hog and so many more...

truth is, i have seen more virus in computers equipped with 3rd party antivirus...