Comodo is offers one of the finest FREE internet security suite from the competition out there, or that is what I felt during my last 4 months of testing/using.

The first thing you will notice about the antivirus is, IT IS FREE and yet Fully Configurable. It can't get any better than that, it's firewall is robust and you can configure it to block any certain website, range of specific IPs, Even, any MAC address and it's antivirus engine has a really nice detection rate.

The next thing is, it DOES NOT slows your system down. Seriously, it is lesser on ram and eats less resources, making your PC secure as well fast.

Another very good feature I found about it is, It's Traffic widget and animated start bar icon which shows the estimation of how much data is being sent and received.

I don't find any negatives in this AV as far as I am using it. It is seriously good protection with unbeatable price.