Checkpoint has anounced a mac vpn client. I have not had time to do any research on features, OS X compatability etc, but they did send me notification of the announcement. We use checkpoint Firewall1 and VPN1 exclusively at work and I know they heavily leverage IPSEC along with some other topshelf technologies. It might be worth looking into considering Checkpoint is the number one commercial product in this market space. From an admin's perspective, this is a massively positive development for the mac platform. If you happen to have a spare machine and enough spare time to test it out, we would all benefit from anything you discovered.