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.
To receive the best value though, it is advised to go for the VyprVPN premium. It starts at $12.95 monthly and $80 annually, adding the ability to establish connections on 5 devices simultaneously, along with access to the Chameleon Protocol and VyprVPN Cloud. P2P/Torrenting in enabled, which means you can easily begin downloading your favorite movie/TV show torrents.
Beyond those two factors, it’s difficult to make blanket statements about what makes a trustworthy VPN. At the bare minimum, a good VPN provider should not collect and keep any logs of its customers’ browsing history. If it does, that puts your privacy at risk should someone access (or even release) those logs without authorization. But deciding when to a trust a logging policy isn’t easy. As the EFF points out, “Some VPNs with exemplary privacy policies could be run by devious people.” You don’t need to have done anything illegal to prefer that law enforcement and criminals alike not have access to a browsing history that may include your bank, medical websites, or that one thing you looked at around 2 a.m. that one time.