Have owned 2013 GS350 AWD for two months and really enjoy driving the car. I drove Infiniti Q50, G37x, M37, Hyundai Genesis, and BMW 335 and picked the GS. It had a solid ride and quality unmatched by the others.
Love all the electronic gadgetry particularly the sound system, blind spot monitor, park assist, and large screen. I like the exterior design, especially from the rear. The exhaust tips look awesome. The quality of the interior is first class. Initially I thought the seats were too firm but I have grown to like the firmness.
Could always use a little more power. For a car in this price range HP in the range of 350 to 400 would be nice. Initially I had some concerns with harshness of ride but determined the tires were over-inflated by 5-6 pounds. After correcting tire pressure the ride is much improved. I find the navigation system somewhat complex to use.