Shimo is a super-slick client to connect to various Virtual Private Network types. I used it for a Cisco VPN and it worked very well. It just camps up there in your menu bar and was extremely easy to use.
Migration Score
GREAT
Migration Options
Network Manager
At least for my needs to connect to a Cisco VPN, the Network Manager that comes built-in just needs the vpnc package installed and it has almost the same user experience that Shimo provides.