PPTP
Widely supported
Weak
Microsoft Point to Point encryption WEAK
L2TP
Widely Supported and strong security
Performance suffers
complex
firewall blocking
IPSec (AES, Certificates) STRONG
SSTP
Firewall Traversal
Compatibility and Proxy Issues
SSL 3.0 WEAK
IKEv2
Mobility Support
Limited Support
Firewall Blocking
IPSec (AES, Certificates) STRONG