Being serious, AntiVir is better than both (slightly).
I've used both and didn't find much difference in their performance.
There's a new kid on the block though recently released.
Have a look at AOL Active Virus Shield which is basically Kaspersky Anti-Virus with a few features disabled. What's more, it's free. No other free anti-virus software comes close for detection and removal capabilities!!
make a poll dude