Light on the resources, clients for many OSen including Windows, OS/2, and Linux. Geared towards corporate multiuser licensing though. We have it on our mail server and desktops. I like it.
And less likely to let that "Magic Lantern" CIA virus through perhaps?
They have demos on their [link|http://www.sophos.com/downloads/products/|website]. You have to request a password to access them.