I've had no serious issues wth Jaguar build quality or service in nearly 200,000 miles of driving them. As I remember, they far less troublesome than a number of 7 Series BMWs' I drove around a decade ago.
The XJ, in all it's forms, has been an excellent car from the X300 models onwards.
I look forward to seeing, and eventually driving, this new XJ.
...'T'is too much proved, that with devotions visage and pious action, we do sugar o'er the devil himself...