Good, Not Great
Qihoo 360 Total Security Essential 8.6 packs in more security-related bonus features than any other free antivirus I can think of. Those features would be a lovely addition to an excellent free antivirus. The problem is that Qihoo's core antivirus protection doesn't quite measure up. There's not much to go on from the independent labs, but its scores in our own malware blocking and malicious URL blocking tests were just average. And somehow going from the previous edition to this one, its antiphishing score went from near the top to near the bottom.
If Qihoo's many extras fill you with delight, you can go ahead and use it. But if your aim is to get the best free antivirus protection you can, there are better choices. All five of the independent testing labs that I follow include both Avast Free Antivirus 2016 and AVG AntiVirus Free (2016) in their testing, giving them good marks overall. Panda Free Antivirus (2016) includes a collection of bonus features that almost rivals Qihoo's. All three are Editors' Choice winners for free antivirus.