I have the lovely privilege of maintaining our computers at the office, 4 Win towers in house, 4 Win laptops and 1 Linux server. We were using AVG free, then I got my U3 drive that ran Avast and upon insertion, Avast found infections.

Sounds like you were in breach of the “AVG Free” licensing T&Cs! Hope you aren’t using Avast Home for commercial purposes as that would be another breach.

Additionally, AVG Free doesn’t scan to the same depth as the paid for version. We should always remember that the free versions of many security apps are cutdown versions.

It is also possible that people who run with Avast could switch over to AVG or another antivirus and see viruses being detected. No security product is 100%!