In terms of wear from starting, I'm not overly concerned. One of the many things that defeats the start/stop is if the engine is cold. It honestly has not been cold enough to figure out what that temp actually is, but most of the concern is on cold starts causing wear. On top of that, it appears they've built some strategies into the engine to keep the oil where it needs to be - note that to check the oil level, you have to wait at least 15 minutes after the engine was running to get an accurate reading (see the edmunds story on the dealer who didn't get the memo and overfilled the engine with 10 quarts of oil!).
Will it be harder on the starter /battery? Perhaps, but those are supposedly engineered to deal with it. The battery is an AGM from the factory.
There are a whole slew of things that will prevent the start stop from working. Off the top of my head:
-Engine too cold
-Demand for Heating or Cooling (though it will shut off if the demand is not High, and then restart when it thinks it needs to)
-Steering wheel angle is high (ie: in a turn or actively steering).
-Any motion what so ever, including just twitching your foot on the brake - its much more sensitive than the last car I drove with Auto start stop - a bmw X5.
-Tow/Haul mode shuts it off
-Low battery charge
-Windshield defrosters are on
and the list goes on, and on...
I wasn't sold on it when I first experienced it, but it is pretty easy to get to it to do what you want...