It's been in three times for VANOS solenoids (though in fairness the first two repairs were just disassembly and cleaning - they replaced them the third time and it seems to have held). I had the steering column replaced after it repeatedly refused to unlock. I had one especially beguiling incident in which the entire audio system (including the bluetooth and even the turn-signal clicker) failed - it turned out to be that a vapor barrier in the driver's door was mis-installed and water got into the floor, shorting everything out - this would have been horrifically expensive to repair out of warranty. I had the battery go when the car was only about 3 years old, with less than 25K miles. It's in the shop now for a leak in the washer fluid system and a squeaky steering column.
All of these things happened within 23,000 miles (I bought the car as a CPO model when it was 2 years old and had only 13,000 miles on the clock).
I will say that my dealer (BMW of Minnetonka, MN) are professional and friendly, and I've always gotten a BMW loaner when the car has needed service.
I LOVE the car (330i with 6MT and Sport, Premium, and Cold Weather packages but no iDrive or Adaptive Steering) from a driving perspective and I'm not that bothered by the reliability issues in light of the fact that it's under warranty and I always get a nice loaner, but if I were paying for these repairs I'd be very unhappy. I will almost certainly get a CPO 335i as my next car, and hopefully NOT suffer a ton of HPFP failures!