My vote goes for Qihoo 360 Total Security (not for the smaller Essentials brother, as this one is updated seldom), because it feels light even if settings are maxed out, has Avira and BD engines as bonus (however I rely on their own engines only), has proven fast detection rates in the past and has, just as
@TheMalwareMaster a good HIPS system which seldom disappointed me (no idea if you would consider chinese PUP/PUA as dangerous, QTS360 definitely doesn't even with their PUA-detection feature enabled). It most of the time blocked different infection vectors (Autostart, altering files just as ransomware tries to, block creation/alternation of processes...), even without signatures.
Biggest point for me was the regular update of the 360 Total Security suite, however they don't state what they change, but it becomes better and better.
Maybe you also might want to have a look here, although it's only about free AVs.
VERSUS - Free Antivirus of the Year 2015 [POLL]