I can't speak for the X11, but I can say the XX4 is one of the easiest to drive 4wd's out there. I've had very good luck with the Robbers setup, and with shock tower braces, front pin brace, and front hub carrier screw mod, it's durable as well. And at least in the States, parts are still easy to get and inexpensive. The sealed drivetrain keeps maintenance to a minimum compared to many other belt-driven cars, but it also makes it a little more difficult to wrench on....that said, as long as you keep an eye on the belts and retain the slipper clutch, the driveline should prove trouble-free.
I love mine and wouldn't part with it for any price
