When the police officer has his own choice, he almost always selects a DA/SA model. Because his ability to shoot his sidearm well is a key factor in his survival, he takes every advantage. Which action is best seems to come down to safety/liability and case of hitting effectively. Certainly Glock went a long way toward providing the safety of a deliberate trigger action and uniform trigger pull resulting in improved hit results.
Other manufactures have moved to make DA triggers easier to shoot well. Para Ordnance's LDA trigger is a case in point. For those who can't handle the sight of a cocked hammer on a 1911, Para Ordnance created their unique LDA action that provides a hammer-down carry mode for the 1911 pistol, but permits a super-light DA stroke to a nice SA sear release. One has to try a Para LDA to truly appreciate just how nice the trigger can be.
Other manufacturers have begun to develop much better DAO triggers, ones that allow the user to shoot them with ease, and get hits nearly as easily as they can with a single action trigger. Heckler & Koch has offered their superb LEM trigger action on some of the USP pistols. I recently tested an H&K P2000 with LEM trigger and was most impressed. The LEM module on the P2000 provides a light trigger take-up to a nice five pound sear release. Most importantly, when the pistol cycles, you don't have to use a full trigger stroke to reset the sear, just a short reset of the trigger and you are ready to fire again, much like shooting a SA pistol. The instant you relax your finger forward, the hammers lowers to the rest position. After using the H&K LEM P2000 I felt I had finally found the perfect "copper's" sidearm. A trigger providing the appearance the administrators like, and the trigger pull the shooter can shoot effectively.