I have a love hate relationship with Qihoo. What most people don't realize is, privacy policy means nothing. They could be taking more or less than what they say they are unless you get Emsisoft which allows you to turn off encryption of data and read everything they are sending to their own servers. You the individual have to say "hey I trust Qihoo as a company" to use it. Qihoo does take data, and it does sell data to make money. I have no idea if they anonymize it before doing it. Obviously more than Qihoo does this but many AVs anonymize it before using it (like Avast, Emsisoft, etc).
If you trust the privacy policy and feel they won't overstep it, it's as good as any other privacy policy out there. They claim they won't share personal user information and these include:
Source:
360 Total Security | Download Free Antivirus for PC
Since trust is user choice, you will have to decide to use it or not however protection wise, I recommend it. For free AV, it's probably my favorite in protection, system impact, resource usage, and control over detection (no forced quarantine/deletion by changing one setting).