If you want a short and smooth trigger, DAO isn't the way to go. I've been checking out a lot of these lately and I've yet to find one with a trigger that I actually like on these. Some are gritty, some are heavy, and some are just all day suckers. You start pulling the trigger at 3am and at noon it goes bang...
The XD and M&P would be SAO and the trigger can easily be achieved, just not from the factory.