Here is one that really annoyed me!
Source: http://www.vpnbook.com/freevpnVPNBOOK wrote:PPTP (point to point tunneling) is widely used since it is supported across all Microsoft Windows, Linux, Apple, Mobile and PS3 platforms. It is however easier to block and might not work if your ISP or government blocks the protocol. In that case you need to use OpenVPN, which is impossible to detect or block
With the right tools, Openvpn protocol is as easy to block as any other