2-3 years ago we used AVG in our builds , it became bloated and we switched to Avast cause it was less overhead, the company i work for now recommends Microsoft Security Essentials, it seems to be okay but i personally wouldnt use it on my machine. for a free AV you can't beat Avast, comparing a payware AV to a free AV is a big diffference. NOD32 if i paid for it i would expect better performance over a free AV. i am just not gonna shell out money for a Pay AV just so i can have the fuzzy feeling of being able to call someone when i get infected. but that's just me. i am computer tech for a living so if i get infected. lord forbid. i just remove it and move on.