I have the National Luna setup on my Jeep and am very happy with it. It works as advertised and is easy to install. I have not seen the Xantrex in person, but it would appear to work in a very similar fashion. You might give Wil at Sierra Expeditions a call as he sells both units. FYI, I did replace the 85 amp solenoid that came on the NL with a 200 amp model.
I have the Pathmaker installed in my rig.... and I dig it! I will be getting the remote for it so I can monitor what's going on and combine batteries (I have the relays under the hood and the control panel in the back of my truck)
Pictures on request if it helps you decide
Dave