Iâ€™ve got a MS ISA 2004 server, and some colleagues that connect to the office remotely, using the built-in windows PPTP client.
After using Microsoftâ€™s PPTP server for about 6 years, Iâ€™ve totally had it. Iâ€™m tired and sick of problems with networking infrastructue (passing GRE through firewalls), the lack of easy error reporting functionality, etc. Every now and then connections donâ€™t work, and rebooting a firewall here and there usually solves the problem.
After thinking about it for a while, I decided to ditch the MS PPTP server, and implement an OpenVPN server for my collegues on the road. Iâ€™ve been using OpenVPN for a while now as well, and Iâ€™m a big fan.. Iâ€™ve hooked up several data centres and remote locations using OpenVPN, and it has always been a rock solid solution. It can get a little complex at times, but itâ€™s definitly worth the effort.