I have never found any Viri in a Linux based system, but I keep ClamAV installed to help protect windows computers that I may communicate with.

I use Avast on the one Windows machine that we use to download coupons, the only thing I can't do in Linux. Since I don't surf the internet in Windows, I haven't encountered anything that would infect the Windows machine, so, I can't really judge the product on it's merits.

I have seen a post though, that said that their anti-virus for Android (Which I probably don't need either), comes with a lost/stolen phone feature similar to Prey. I might take a look at it in the future. I'm still looking for a good app that will track the phone if it is lost or stolen.

Since I don't use Windows, I have little use for an anti-virus that checks Windows files. I have Fedora hardened with SELinux and a double firewall (router & desktop), so, I feel pretty secure here. There still hasn't been a virus or trojan that has spread in the Linux universe, so, I'm feeling pretty safe here.

BTW - I discussed the recent Apple virus with a niece who owns a Mac laptop today, and read through explanation of how it propagated. It seems that the user is asked for permission before the trojan is installed, and, without that permission, no infection. Unlike Linux, there was no message in the update window as to what was about to be updated. Was it Automatic updating that was the problem? And why would anyone except an update without an explanation? I saw the window that opened in a post (sorry I don't have a link handy), all it said was an update was ready and permission was needed for it to continue. I'm glad I get to choose what and where I get my updates from. I thought Apple and its BSD based OS had similar features. I'm not a Mac user, so, can't say for certain. Just happy I'm a Linux user.