The paradox of choice
Searching for information on setting up an L2TP VPN takes me here, where I get to choose between OpenSWAN, KAME and some OpenBSD port. Searching for information on setting up a PPTP VPN takes me here, where I'm told exactly what I need to do.
Given choices, I chose the one that reduced my choices. THERE IS A LESSON HERE.
(Sadly, I'm now going to have to deal with L2TP anyway because something in the intermediate network is dropping GRE)