We live near Tacoma, Washington. We don't get a lot of snow but what we do get, the JX should handle nice. It handles very well in our weather ( we don't get as much rain as people think).
Today we were driving through Wyoming when out of no where came Close to 50 mph winds and sleet/snow. The car handled great. I was doing 70 mph and slowed to 65 mph. The forward collision warning system and front auto breaking functions shut off (DCA light comes on and kicks off the nannys except for blind spot warning and lane departure warning systems which work great when you can't see the road. If there is too much snow on the road, the cameras can't pick up the road mariings.
Before we headed west, I called an Infiniti service department in Wisconsin to see how the JX/QX handle in the snow. They aren't allowed to use chains or studed tires. He said their JX/QX vehicles are equipped with the Bridgestone Dueller mud and snow tires (same as on my car) which his customers are having good succes with. He stated that they have done well in up to a foot of snow.
Tommorrow we are heading west and might hit snow in Idaho and the Snoqualime pass. I'll report on that experience.