PPTP - PPTP has been around since the days of Windows 95. The main selling point of PPTP is that it can be simply setup on every major OS. In short, PPTP tunnels a point-to-point connection over the GRE protocol. Unfortunately, the security of the PPTP protocol has been called into question in recent years. It is still strong, but not the most secure.
As with the previously mentioned VPN services on this list, VyprVPN also provides an extensive DNS Leak Protection (Including IPv4, IPv6 and WebRTC protocols), which is tested by clients. VyprVPN includes support for a L2TP/IPSec protocols as well as OpenVPN. VyprVPN has a no-logging policy. VyprVPN also enforces all IPv6 traffic to be via its network and avoid any IPv6 leaks. Overall, that is a pretty solid VPN in security-wise.
Closely control access to your VPN box, whether it's a concentrator or Windows machine. In the case of a Windows server, put the machine on a separate domain and have only a few accounts on it. Use the strongest possible passwords, and store and swap them out appropriately. In the case of a hardware device, disable insecure protocols, such as FTP and Telnet, that pass your logon information in the clear. An insecure VPN concentrator box or unpatched Windows VPN server presents a much easier target than do VPN keys that must be brute-forced.
We summarize the protocols above, and look at them in detail in VPN Encryption: The Complete Guide. Although L2TP/IPsec is fine for most purposes, we only really recommend OpenVPN and IKEv2. OpenVPN is very secure if properly configured. Indeed, Edward Snowden’s documents showed that even the NSA can’t crack well-implemented OpenVPN. It is also supported by almost every provider. But it is relatively slow. The newer IKEv2 is much faster and is considered secure, but has not been battle-tested in the way that OpenVPN has. It is not as well supported at present, although it is increasingly popular with providers thanks to its speed advantages over OpenVPN.
HotSpot Shield is a product that has had some ups and downs in terms of our editorial coverage. Back in 2016, they picked up some very positive coverage based on founder David Gorodyansky comments about protecting user privacy. Then, in 2017, a privacy group accused the company of spying on user traffic, an accusation the company flatly denies. Finally, just this year, ZDNet uncovered a flaw in the company's software that exposed users. Fortunately, that was fixed immediately.