I bought my 239 with the DA/SA trigger. I prefer that setup, and my other two Sigs that I carry (P226 and P232) also operate identically.
Ultimately, I settled on DA/SA for the range. My thought was this: The likelihood of ever needing to actually fire my gun in a defense scenario is very slim, which means practicing and target shooting will probably be 100% of the rounds put through my handguns. I prefer SA for target shooting, but I want a DA first pull with no safety to operate for defense. I practice double taps with the DA/SA pattern every time I go shoot. To me, it seemed like the best way to go.
My dad on the other hand is completely sold on the Sig DAK trigger system. He absolutely loves it. As a LEO, he is big on the fact that every trigger pull is consistent, and there is no way for one of his officers to forget to decock the hammer before placing their sidearm back in the holster. He always carried DA only in the past, but doesn't miss that heavy DA trigger pull.
-SF