 After owning three Q45s and a QX4 and having been extremely pleased with the Infiniti experience, I recently went out and purchased a 2005 FX45 with 14,000 miles on it.  The vehicle is a dream, as it handles like a sports sedan.  The abundance of power provides frequent thrills, ride quality is superb, and the absence of road noise leaves me constantly wondering if I'm really in an SUV.  On top of all that, the vehicle is rock solid.  I recently completed a 1,100 mile round trip and averaged approx 18 mpg while driving at average speed of 75-80 mph between San Diego and Beaver, UT.  My driving is 80% highway.