Tested BMW x5, MDX, BM350 and RX350 and GX460 on local road, loved RX350 but went with Gx460 with regret not testing it on highway. Thought we will get roomier and more conformable ride than rx350 but got sea sick the first 50 miles driving it. This truck ride very bumpy and shakes on high way, it made us sick and dizzy (never had this problem). Be care if you have kids. Gas mileage is very poor not an ideal day to day car for the family, avoid it if you can. Traded in for a 2011 RX350 later and much happier now.
We owned a '09 GX470 for two years before trading in to a '11 GX460 and i agree that the ride is stiff unlike the old GX. the base model GX460 lacks the height and suspension adjustment that is available on the premium model.