There is a good chance that VPN Client's from different vendor's will NOT work on the same machine.
I know that Cisco's and CheckPoint's do not work togther on the same system. One requires the Windows IPSEC Subsystem to be enabled, and the other requires it to be disabled. Documentation has indicated this is because the MAC Shim bindings to the adapter.
I would not expect to see the vendor's getting together on this anytime soon.