I got a JD Power Survey form to fill out when I got my new car last May. The survey is better than nothing, but unless a car were ranked low than median on the JD powers I wouldn't even consider the rating in buying a car.
I should have kept a copy of it but I didn't. It was underwhelming. My car had two minor as delivered flaws which were caused by the otherwise outstanding pre-delivery prep. One of the flaws was not including the front license plate mount that I wouldn't have used anyway. The other flaw was some minor widget that wasn't installed right and I fixed myself in 5 minutes. 8500 miles later, no defects.
In filling out the form, the two flaws got reported, but I don't think that the survey results show that they were noting of signifigance.