PPTP (Point-to-Point Tunneling Protocol) has been around for a long time. It offers good basic online security without a heavy CPU overhead. It is light, quick and responsive. It is the most supported protocol by a large variety of devices including mobile devices. It is a good choice if OpenVPN is not supported on your device.

IP Security protocol uses an AES encryption algorithm with good security. It is a bit heavier on CPU overhead. It is a choice if OpenVPN is not supported on your device.

The OpenVPN protocol uses SSL and TLS for encryption and use the OpenSSL library. OpenVPN provides the best encryption strength with the lightest CPU overhead, making it the best choice if your device supports it.

Protocol PPTP IPSec OpenVPN
Secruity Good, basic encryption. Good, basic encryption. Best encryption, no known vulnerabilities.
Encryption 128 bit 128 bit 256 bit
Speed Fast, Low CPU overhead Medium, Higher CPU overhead Best performance
Compatibility Windows, iOS, Mac OS X, Android, Linux, DD-WRT iOS, Mac OS X Windows, iOS, Mac OS X, Android, Linux
Setup Built into most operating systems. Easy. More complicated, requires some configuration. Easy with OctaneVPN client software. Can also be custom installed if desired.