PPTP should not be used anymore. Even Microsoft (which designed the protocol) has advised against using it.
One protocol which has not been mentioned is 'OpenConnect', which is quite simple to set up (you just need to make the keys and to edit a simple .conf file), but after that just works and OpenConnect works fast.
OpenConnect works fine on all OS and mobile platforms. OpenConnect was initially set up by Cisco (the makers of high quality routers), called 'AnyConnect' in Cisco-speak.