Avast..Avira..or AVG.....?

Actually I tried all 3 yesterday to a friend computer that wanted a free antivirus.I uninstalled AVG after an hour,the new one is very aggressive it gives so many false positives.Next was Avast due to good reviews but I uninstalled it because in order to retrieve updates it required registration ,user name and pwords ( asked me to use credit card)although I had the free version.Also Avast interface is a little retarded. I had no problem installing,updating and configuring Avira so this was the winner for me.