I've been using Antivir and its the best, it found viruses that most scanners missed including PC-cillin which I had heard was supposed to be the best...not. Antivir all the way.. BTW, those were genuine virus files.
Only problem is, there is no automatic update but updating is pretty easy.
Another thing you have to know about Antivir real time protection is that it works differently as it doesn't scan everything when you download it, however if you go to run any file it will scan that file only then. Some people like that, some people dont. Personally, I like it a lot as it hardly consumes any resources and is efficient enough.
The On Demand scanner works just like everyone else's.
To the poster who thought Antivir was malware putting virus' on the computer and then offering to remove it, that is simply not true. Antivir seems to label some of the virus files differently than the other scanners and therefore the names of the virus files wont correspond. I dont know why they do that but most of the virus files are labelled correctly with their generic name that's common to most scanners.
Antivir is easy to install and easy to uninstall (very clean) so might as well give it a try.