I always hear people say JDPowers is bullshit, but they never supply any other studies.
Well, I don't know about the USA but here in Germany there are two annual studies based on statistical data and not on customer's opinions, which are very influential: The "ADAC Pannenstatistik" and the "T?V Report".
The first is based on the data from the repair car fleet of Europe's biggest automobile club, the second on the data of the mandatory technical inspections every car has to go through every 2 years in Germany.
Edit: I just read the results of the German JD Power survey and frankly it's all a bit weird, because it often contradicts the objective results in above mentioned studies. As I understand it, JD Power uses online forms sent to random people. And for a certain car to be listed, it is enough to get 50 (!) replies for it.
That is not representative and the system obviously prefers unsatisfied customers, because it is a known fact, that the chances of filling out and sending back such a form are considerably higher with people who have a complaint.
So the results are always warped, because there are of course always more people who complain about a Golf, than about a Jaguar for example. Especially the owners of "stylish" cars are also more forgiving, than salesmen who drive a Passat.
Also I don't see any equational formulas or factors in the JD Power survey, which take into consideration, how a car is used -- it's one big, undifferentiated list.
And of course it is more likely to complain about something for, say, a Mini owner, than for a Toyota Prius owner
Another point is, that also the customer service of the car maker is taken into consideration. It doesn't reflect the fact, that more and more car owners do not let the maintenance and service be done by the contractors of the car maker anymore. I am such a person. The VW service is a nightmarish mixture of arrogance, incompetence and overpricing. Always has been ever since I had cars from VAG.
Yet I always liked the cars. Therefore I only go to independent garages like A.T.U., who offer good prices, excellent service and are often much more competent, than the VW "sorry, we are currently on lunch break" idiots.
So I stand to my opinion, that user surveys are mostly useless.