Shortly after I purchased my X3 I drove from Austin, TX to my home in New Hampshire. I learned to really appreciate the car, the ride is great and the convenience features make it a pleasure. Comfort access is my favorite feature. I was very impressed by the handling after taking unfamiliar exit ramps quicker than I should have. And I like the NAV directions in the dash between gauges. Very convenient.
The only quirk I have noticed, that I hope it something I can set, it how long the interior lights stay on once I have parked and turned the engine off. I need to gather my things (cell phone, glasses, etc). I'd like the interior light to stay on until I open the door, not in the allotted 5 seconds or so. And I would like the car to unlock automatically when I park and turn the engine off. Small pet peeve. Probably settable in the myriad settings in iDrive, just haven't explored it enough.
On a minor note, I wish the engine sounded a little more aggressive. The exhaust note is too muted for my taste. I had a 335i coupe and it sounded great under throttle. But the quiet exhaust is fine here I guess. It suits the car.
It takes time to learn some of the quirks, like the climate controls. I found my feet getting very hot at times. And the "auto" temp setting is not really auto - the fan settings are independent of the auto system. The fan setting selected will be the max setting used by the climate system.
And oddly, the dash display gives off some ambient heat - I lowered the brightness and the heat is less.
A rear fog light, common on Volvos, would be nice too.
As far as the Sport / Comfort / Eco Pro.... I found EcoPro to be sort of useless. I usually drive in Sport under 45-50 mph, then switch to Comfort. I like the extra oomph in Sport when merging into traffic.