To be entirely honest NAV has improved immensely over the years. Their detection rate used to be absolutely HORRIBLE(something like 70% when their nearest competitor was in the 95%+ range.)
They have figured that out a little bit, I think they are on par with the other leading products these days
That being said it still has a few drawbacks: It costs money for a yearly subscription. There are free antivirus tools(Avast, AVG, Avira, Bitdefender.) Coupled with other free tools like MalwareBytes it is a waste of money in my opinion. It is annoying. Always asking you to try Norton Internet security, and basically advertising other Symantec products to you constantly. Lots of reminder popups to do scans and things rather than just intelligently working while you aren’t on your PC. If I pay for something I expect no advertising.