IMO before finalising about buying avg try it for some days to observe how nice it plays with your other security solutions. Give more importance to its performance like is it slowing down your browsing? or it is slowing down your booting etc. For about its malware detection capability go to site like av comparetive and virus bulletin and observe the curent performance of avg. Also before finalising any av its a good idea to go to their forum and observe its effectiveness, which would come in handy if you run into some specific problem. Observe things like is there are any thread which are unanswered for quite few time or what are the quality of the answer given.