I have been using it for the last year. It does pop up and tell you when something is trying to get in. It gives you the option of allow or deny.
I downloaded it by accident on my company computer. My problem is I tried to delete it that is a nightmare and now I am stuck if I have to send my machine into the company I am going to have to hear the "I broke the rules speech" Blah, blah, blah. We are not suppose to download any programs especially any virus protection because we have Norton Virus protection.
That said...My opinion is it has not seemed to hurt anything and I think it helped. But if you do not like it grtting ride of it is very difficult.