Is MacScan something I should get?

Hi,

I'm a new Mac user and wondering about getting some type of internet protection for my new iMac.

I hear a lot of people say, "No, you don't need things like Norton Anti Virus, etc., even for Mac, because your Mac is generally safe."

However, I have seen the MacScan and wondered if if should be something that I add to my computer?

Thanks for help,

Lee