As like any computer paranoid user , I would always have an anti virus installed into my computer before I install other applications and I have always been using Symantec's Norton Anti virus. The one weak point I know of many years of using it is that it does take up a bit of processes and can be rather bloated and when I do a full hard disk scan, it takes up so much resources that I have to suspend all my activities including games and just leave it alone. I switched over to Clam AV solutions and it feels so light for my processes and when i do a full hard disk scan, I still have my games on and chat on and other applications and NetBeans IDE still running while ClamAV does it's scanning faithfully. I wonder what would happen if Symantec decides to adopt and intergrate ClamAV's engine into theirs and decides to find improvements to make a bloated Anti Virus software into something lighter. That would be good for all Symantec users if the software becomes lighter and still retails it's power to handle virus.
I think ClamAV needs to catch up on the area of auto protect which most anti virus software have already embedded this function in it's software since past.