The reliability of the powertrain is rock-solid. The VQ35DE engine will go for well over 300,000km without any major issues, and the transmission will give you no problems. One thing to watch: on areas with salted roads or by oceans, rust can be an issue.
Unlike many domestic vehicles, the Pathfinder *feels* solid. The steering wheel, interior controls, and doors/hatches on many other vehicles feel hollow and cheap -- with the Pathfinder they are heavy and durable, and will stand up to abuse.
The All-Mode 4WD is a great feature to have on icy Canadian roads. The 240HP always gives me plenty of passing power, even in the mountains, and being able to tow 5000lbs without sweating adds credence to the "utility" in SUV.