What is the best VPN for Mac/Windows/Linux Server

Well that may be because VPN technology is not that easy... OK the OpenVPN docs are probably a bit too long, but there are plenty of easy step by step explanations on how top set it up available on the net. Did you try one of these? Like this one or this one or this one

OpenVPN is a great solution, but OpenVPN Access Server is even better. It's easy to install with pre-compiled binary packages, and a breeze to setup with the use of a web interface. It does require a license though. They give you two concurrent connections for free, and then charge $10 per connection afterwards. The clients can log into a web portal that then provides client binaries and instructions on how to set the client up. It's easy to configure and powerful, feature rich, as well as simple to understand. Check it out.

I blogged about it here: http://jordaneunson.com/?p=74

Check out OpenVPN Access Server here: http://www.openvpn.net/index.php/access-server/download-openvpn-as.html