15,000 miles on my 2011 X3 and no issues, other than the hesitation off the line, which seems to have finally gone away.
I've had 7 BMW's and find them to be reliable, although I think you need to be a car fanatic to own one. Something about being willing to pay the high cost for repairs in exchange for the best driving experience. I plan to drive BMW's as long as I can continue to afford to own them. A little DIY for brake jobs, and routine maintenance helps to keep the cost of ownership in check.