The efficiency of either antivirus system largely depends on the date of its last security update. Both Norton and McAfee regularly update their virus definitions to account for newly discovered viruses. As such, a recently updated version of Norton will offer better security than an older version of McAfee, and vice versa.
Beyond their virus protective features, both security suites offer different features that may appeal to different uses based on their individual needs. For instance, in 2014, Norton came with a browser add-on that monitored a user's web activity and screened each webpage for possible virus or malware. This protective feature helped reduce the risk of visiting compromised websites. It also IM and Chat protection and offers extensive support across different operating systems, including Android.
On the other hand, the McAfee Security Suite comes with advanced screening features such as Parental Control and Spam killer that allowed users to filter the amount and type of content passing through their computer. It also offers strong support against phishing applications. All told, Norton's key strengths lie in its virus protective features, firewall, backup option and spamming filter. McAfee, though not as robust, offers slightly better usability that may appeal to inexperienced users.