No, I would not go back. I am now driving a 650GC xi and I miss the adaptive drive - yes, I miss it and I'm in a car. So I suspect the difference would be even more noticeable in the X6.
My only recommendation would be to test drive one extensively and see if you notice it. If you do, then I must suggest my old car which for some reason they have priced crazy low. But it has just about every option except for the leather dash and never was in an accident.
http://www.bmwautohaus.com/certified...ed5a71035d.htm
As for Brett Midgley. His number is 314-880-8416.