I can't remember where on the forum I saw reference to it, but clearly, there is an issue about brake dust on the rear wheels and the concomitant brake pad and disc wear that fellwo forum members have reported. Certainly, I have never known a car where the back wheels suffered from brake dust pollution to anything like such a degree. And yet, in the JD Power survey, the XF gets No 1 spot for braking!! Regardless of the brake dust and pad wear issue, what is so particularly special about the braking on this car? It seems satisfactory enough, but, for heaven's sake, all of our cars' rear wheels are constantly being covered in brake dust in a most unnatural and hitherto unforeseen way and others have reported ridiculous premature wear on the pads - how on earth does the XF rank 1st out of 100 cars for braking? It simply makes no sense at all! And what is all this about Jaguar Assist taking hours to turn up or to respond to problems leaving people at the side of the road? Do Jaguar have a proper, efficient and professional support team in place or don't they? And why, honestly, is there this extraordinary secrecy about the malfunctioning Sat Nav? I cannot get my supplying dealer to admit there is a problem at all! Interesting that the XF does shamefully - (let's face it) - under Reliability in the JD Power - hardly surprising in view of all the concerns that forum members have written about. It's a little tricky to keep the faith, I find.