Real World System Impact => Bitdefender (with Photom)
User Friendliness => F-Secure
User Interface => F-Secure
Level of Protection and Features (eg: Antivirus , Firewall, Behavior Blocker) => Detection : Both . Behavior Blocker : Bitdefender (AVC is better than DeepGuard)
Real World System Impact: Bitdefender (but F-Secure is not too heavy)
User Friendliness: F-Secure
User Interface: F-Secure
Level of Protection and Features (eg: Antivirus , Firewall, Behavior Blocker): Bitdefender (for its BB)
Overall Winner: Bitdefender
But, F-Secure is less buggy than Bitdefender. I've tried Bitdefender time by time and Windows always got crashed (fresh install). F-Secure IS does not contain so much bloatware as Bitdefender (Total).
We're talking about Ram usage, user frendly and protection but lets talk about money to, F-Secure its asking to much for to litle, when Bitdefender has plenty to offer.