I use Bitdefender Free on one PC. Set and forget it, no popups, quiet and trouble free. So I have no complaints with BD.
I use several PCs, including one in my home entertainment center for watching TV and playing games. Rarely open a web browser on that one unless I am installing or updating something. It is running Windows 7 Pro.
I also have a paid AV with several licenses available, that I use on my main PC, yet I prefer to run this little freebie on my entertainment center. So I guess it depends on your usage and needs. I feel that with the unintrusive behavior and low impact, along with with the high detection rate, it works great for a gaming or entertainment center. But for heavy web usage I would probably choose something else.