If you have been following my posts in the Hub with Vipre, you will notice only 3 occasions where something either got by Vipre, or at least gave it a run, now in several weeks of hammering this product, I call those very good results. You may also notice I test it with default settings, HIPs and IDS are not on. I run it on default settings on my main host as well, and trust it. No security application is 100%. That said, adding NVT is up to you, me personally, I would find it overkill.