Just straight IPSec with XAUTH. No L2TP. The built in VPN client is *really* dumbed down and very inflexible. No company is going to change the way their VPN is configured just to suit a few android users.
It would be nice to have something that would allow me to create my own Phase 1 and Phase 2 proposals, use XAUTH only, certs, etc... and also be able to configure multiple concurrent tunnels.