After driving an A4 for several years, was in the market for a vehicle with more space, but still fun to drive. The X3 has filled both needs, but thus far it feels like it was $10K too expensive (mid $40Ks) -- after adding reasonable equipment to the 3.0 package. In hindsight, wonder why I did not buy an X5? Ultimately, extra cost up-front vs. vehicles in its class will need to gauged vs. long-term reliability.
The extended moonroof is great -- as long as you leave is closed or drive < 25 MPH (too much noise at higher speeds). Great ride -- have not encountered the stiff ride noted here and elsewhere.
A single CD changer as part of premium audio system? Give me a break. Given vehicle is supposedly built for the X generation -- how about a protective liner for the back cargo area? I don't have a mountain bike, but do have plenty of muddy kids' sports gear.