Techspot has a table of some known bad VPNs, and concludes:

The report does not speculate heavily on Qihoo 360’s motives for concealing ownership of so many free VPN apps, an approach that likely helped boost downloads while avoiding reputational risks. The company, which has well-documented ties to Beijing’s communist regime, may have pursued this strategy to minimize costs and maintain deniability.

For more details on the security issues, this is about the same paper: cyberinsider.com/vpn-apps-used-by-millions-contai…