ikev2 cons:
Potentially compromised by the NSA. It uses the Diffie Hellman process to securely exchange public keys needed to encrypt your traffic. Edward Snowden has previous revealed that the NSA may have discovered a way to break this procedure. These claims haven’t been confirmed, but diligent programmers, including NordVPN, have patched up the issue.
openvpn cons:
Complex setup. Its versatility means that most users may be paralyzed by choice and complexity if they try to set up their own OpenVPN.
咁既然surfshark handle 左complex setup, 理論上openvpn 好似係好啲
source:
https://nordvpn.com/zh-tw/blog/protocols/