No matter what, there will always be pros and cons for AV on your PC, but if you choose the best possible AV with a solid device configuration, I think the benefits far outweigh the disadvantages.
My point was not about the common AV.
I do agree that one needs to have such a tool installed (although nowadays even Windoze comes with one not-too-bad).
My point was about those with strong protection (i.e. over the average functionalities) - usually coming with somewhat more difficult-to-handle functionalities/annoyances (and I'm not talking about the advertising).
But I can also agree that depending on what anti-viruses/protection systems one has been using in his life the experience over what one or another such tool offers and demands may differ.