How different Symantec EndPoint is from Norton Antivirus and NIS

I like to stay informed about software.

So, from what I see in the tests that the most trustworthy tech sites release:

Virus Bulletin tests has to do with Symantec Endpoint Protection, while av-comparatives.org tests for example, has to do with Norton.

And I was wondering what is the real difference between these products. Did they use a different "engine" inside or they just have different interface with different options ?