Bitdefender is a poor av it use to be good but now it is in the same class as norton, norton is the worst av by far because it is so popular it is the first av attacked by viruses and trojans, its detection rate is poor for price.
Comodo internet security free beats all av's hands down:
custom dns: filters bad sites lowering chance of catching something.
Sandbox: comodo sandboxes all apps that are used on the internet.
Firewall: one of the best firewalls
antivirus: has multiple settings high detection rate
Hips : Monitors network and/or system activities for malicious or unwanted behavior and can react, in real-time, to block or prevent those activities like the execution of fake av's.
I own my own computer store every day i see nortons with fake av's, fake registry programs, trojans, backdoors and rootkits same goes for all free ones avg,microsoft security,avast. I have yet to clean a machine that has comodo internet security free on it.
There are a few reviews on youtube check them out its even better.