True we dont have "BEST ANTIVIRUS". Some of these antivirus can detect Innocent program bearing the exetension .exe as virus thereby removing it from the system. some even go as far as killing the system instead of the virus.
Also, that AVG remove a particular virus does not make it best, there may be other virus it cannot detect but kaspasky can detect and remove. and visa -visa.
The best thing is to have more than one antivirus and swap every 2 to 3 months to ensure virus free computer. or possible install different antivirus in different systems and see for your self by scanning effected flash drive.
T hanks