For a start, I would ignore any motoring writer's review of any car. They are paid to do a review - paid by whom? In most cases they will ignore any obvious deficiencies and comment on how nice the stereo is and he pretty the dashboard layout is. And look at the photo of the safety chains on the caravan coupling. The guy who set that up didn't know anything about what the chains are for - they should have been set much shorter.
The the reply by Desert Dweller bags the diesel. On reading the Xtrail forum he referred to I could not see any major problems with the diesel. Yes - they have EGR and DPF problems, but so do all the new diesels. What matters more is how Nissan will treat their customers when they present with their problems. In the past, they have not done very well. As the forum reports, short runs are not good for diesels, so if the intended use is to drop the kids off to school and go for coffee, a petrol engine would be a better buy. If the use is for towing, the diesel comes out ahead, although the modern petrol engines are much better than they were a few years ago.
I won't make any recommendations to the original poster either way, but I certainly would not discount the diesel based on the downers listed on the Xtrail forum - there seemed to be more plus than minus in that as far as I could see.
I have had a petrol XTrail coming up three years, but only done low mileage. It has been faultless, I would recommend it.
Clearly not an off road vehicle, but has compensating strengths, about 9litrs per hundred kms average for a start. The thing is surprisingly roomy, and quite comfortable to drive. Nice high seating position. We bought it as an alternative to a commodore wagon, and feel like it was a very good move.