You may want to watch this lengthy video, where a real phone nerd puts the iDrive to a real test and shows the disappointments. He has an older phone and iOS, but the connectivity issues are clear. He then goes to his cheap car at the end and shows how well it works, without a $250-400 cradle/adaptor:
I am starting another thread as I am off to a bumpy start. Car with 85 miles on it started to smoke and smell from the engine compartment.