i don't have it on my 08, but I would def. use it here in the DC metro area where prices are high and there's alot of urban driving.
OP to answer you question, auto start/stop does NOT materially damage the starter or engine. It's a calculated "wear" by BMW engineers. Does start/stop overtime degrade the starter? Of course. Will you be impacted? 98% of time, no. They probably figured, most cars are scrapped by 150k miles. The starter is made to work maybe to at least 190k miles worth of cold/warm starts. (these are just made up numbers) Therefore, you will benefit from the feature without experiencing the downside.
The same can be said about all the components of the car. They're all made to last at least 150k without any major overhaul or replacement. So it's the same answer to most similar questions:
does pushing the start button degrade the button function?
does rowing the gears degrade the transmission?
does turning on the lights more often degrade the bulbs?
does driving the car wear the tires?
does driving the car degrade components of the car?
yes, but it'll break after a certain period of time or use, and 98% of us original buyers will NEVER see this point. I know I won't be keeping this car after 120k miles.
Finally, OP, if you're really concerned, the major wear on engine occurs during cold starts. You can turn the feature off until your car has completely warmed up, then turn the feature on. That's what I would do. BTW, Road and Track magazine wrote a editorial column on this a few months ago.
Last edited by mdosu; 01-19-2013 at 10:52 AM.