I would like to stress that:
1. There are no OS X viruses in the wild.
2. There is no known, self-replicating proof of concept.
Selfquoting sucks, but here is a history of hoaxes from me:
MP3Concept was a proof of concept for something completely different, it was found in a usergroup and hyped by the antivir company Intego. Sophos' mysterious Mac/Cowhand.A is the same story. These two were not the only false alerts.
I know one trojan, but it has to be installed locally and intentionally. Some genius once activated a script named "Microsoft Office", he got it from a P2P-Network and the file was only a few kilobytes. It deleted his user directory. Stupid^2 but this is a "mac virus" that has got media attention!
So it doesn't really matter what you chose, because everything is good against hot air I wouldn't buy a product because every big company has made an alarmistic stunt by now.
Get a backup strategy and a firewall, don't use the root account if not necessary and regularly update OS X. This makes a Mac as malware proof as it goes in my opinion. I have no need for an annoying email cop program or a Symantec tarball on my Macs! :thumbsup: