I wouldn't worry about issues. They are complex but modern diesel are reliable, quite, powerful and get great mileage. We looked at the TDI hard before any dealers were willing to strike a bargan. I bought my wife a e320CDI (benz) and we love it. It has had an EGR problem which is an issue on a lot of modern european engines. I just unplugged the EGR and clear the code.
I have considered getting the GC diesel a couple of times. However, I am used to Landcruiser reliability and the premium Jeep wants is just stupid and more than makes up for the poor MPG.
Not bad considering it's over 175K miles now.