I have to agree with most of Bern's assessment, except that I think he gives PPTP too much credit security wise. PPTP encryption uses RC4 as well, which has some known weaknesses. It also exposes a lot of information in the unencrypted side channel which makes it even less secure. See this article for some more in-depth analysis of a couple other potential issues. With all of these potential attack vectors it might be worth using for the ease of use factor, but IMO the security concerns merit serious consideration. Personally I'd never use it for anything, and I'm not much of a security nazi.
As far as IPsec is concerned, I agree that it can be a bit tricky to set up a working roadwarrior configuration with PKI, but the ShrewSoft VPN client is pretty straight forward and much easier to get working than MS's built-in client (which has never worked for me - I think it relies on L2TP). Once you get the server side configured properly and learn how to administer the PKI it's really not difficult to get going - but it's still not really something you can just hand to a lay person and expect them to be able to use. With NAT-T in 1.2.3 I'm now using IPsec exclusively whenever I don't need Layer 2 tunneling (where I use OpenVPN). OpenVPN is easier to package in a user-friendly way though if you don't have control of the client PCs as well.
