If history means anything, McAfee Antivirus USED to be a FREE program too. It also used to be good. That was back in the BBS Days and maybe early internet. Then they found out that they could make a lot of money selling it, or something like that. I suspect it's a good business model... since it's hard to steal market share away from Symantec/Norton, Trend, and CA/McAfee nowadays. Give it away for free until it penetrates a lot of PC's and then "It's getting too expensive for us to keep up, you'll have to pay" or it'll just die because it's not being updated enough.
Oh well, enjoy it while it lasts and be ready to switch again when the new freebee arrives.