While I will post more detailed ride review after more miles, initial impressions are below. Had to say I had great trepidation when signing the check-really was worried about this choice for some reason. It felt risky for some reason-maybe it was reading the mixed reviews or just the dollars involved.

The fifty mile ride home soothed me immensely. The rear visibility wasn't a big deal- a little extra caution and a second look was all that was needed. (no backing yet) Ride was surprisingly smooth-even more so than I remembered from the test drives. Even with the 20's, my immediate thought was how firm my 335 coupe rides in comparison. I have been resisting giving up the coupe but the X6 was good enough to make me start giving it consideration.

Back to the OP's question, I would not worry about the ride being a deciding factor between the X5 and X6. The X6 is definitely more car like to me, say 10-20% depending on ones personal preferences. However, they are both so competent in this regard, I would look to other criteria for my decision points.