Well we got home from our trip to the Canadian Rockies in our new 07 X3. Some observations:
Mileage = 24 MPG (US) at 75 MPH with five adults - not too shabby!
Front and back seats very comfortable with the exception of the middle back (no surprise)
Could have used rear air - particularly with the oversized moonroof.
Vehicle held the road like a true sportscar - I was amazed! This X3 is one fun car to drive on the curvy mountain terrain.
Speed, and availablility of more speed, was also amazing - it was like driving with a lone occupant.
Room to fit three average sized and two oversized suitcases. The X3 trunk looks small but you can fit a lot in.
No issues with the tranny - still shifts with no problems.
Love the MP3 reading stereo - bored the three adult children with my 150 song 70's selection of music (LOL)

All in all I am still very happy with this purchase. Too bad it's my wife's car and I only get to drive it on road trips!