Well on my side I was using Quick Heal Total Security on my pc starting from XP pro. I never had a problem with that but just one that is its too costly which I can not afford. It has the best virus detection till now. But it lacks in other aspects like sandbox it does not have, Rest every thing is there a very simple to use interface and every thing Quick heal has is just the best.
I know many of you may not have heard about Quick Heal. So as I cannot afford it so i was searching for a AV which is free and I got avast as highly rated though I don’t like its interface as I do for Quick Heal Total Security 2010 or 2011 but a minor compromise is good as they (avast people) told me that they are going to keep this interface and there will not be any change. But still ok as long as I can’t afford Quick Heal as I m currently not working