Anti-virus software programmed by a malware developer.
Upload local files without user approval.
Install unwanted software in the name of Windows hotfix.
Spy on user's activity and contribute to the Great Firewall.
I have used 360 Antivirus, 360 Safe, Ludashi (A hardware monitoring software by 360), and, they don't cause any threats to my computer. Instead, if someone is downloading files from websites that WOT has rated red, 360 Safe will detect the problem and warn the user that he downloaded a Malware or Virus. Then 360 Safe will put it into the pre-deletion area. You can whitelist it, or delete it.
This website offers a fully free enterprise security solution that is trusted by Google's virustotal.com and actually offers excellent protection. But, the solution along with all other software on 360.cn, does send some of your computer's private data to the Qihu corporation. Be careful!