the reason governments use Norton is because its a big company.
I'm in the process of completing a site audit for a company whom contracted the company I work for to perform a site audit, the have Norton rolled out accross their network. But they also have (from scans that I've performed) a lot of browser toolbar that carry trojan payloads.
The reason I know they carry payloads, when I've been to sites that have dodgy activeX controls that download these tool bars, my free AVG has told me about the dodgy activeX control, and the spyware toolbars it is attempting to download.