A new study by OPSWAT suggests that free antivirus applications The research firm also graphed the location of antivirus vendors. Apparently, 52% of those in the study are European, including Avast, Avira, AVG, ESET, Panda, BitDefender, G Data and Sophos. Meanwhile, 31% are located in the US, including Symantec, Microsoft, McAfee, PC Tools and Sunbelt. Numbers aside, what's your preferred antivirus and why?