I have put several hundred rounds thru a fullsize P320 in 9mm & .40. The LE SIG rep dropped both pistols @ the PD range for T&E. The 9mm is boringly accurate & very mild to shoot. A bit heavier than a Glock 17 so it soaks up recoil real nice.
The .40 is also extremely accurate & easier on the hands than my Glock 23 & 35. I presume due to the very solid steel internal frame & more heft. The polymer frame is also rigid & not as flimsy as many other poly guns. I also shot the .40 P320 better than the Glocks. The trigger is phenomenally better than virtually every other striker gun, except the latest iterations of Styer's S/M/L pistols.
I have basically decided to do the Sig P320 for work & retire my old Glocks. The only thing slowing me down is the lack of light bearing duty holsters & $$$$$.
My agency approved the P250 years ago, but no one carries it any longer. I think the P320 will do well in LE & civillian circles. BTW, the rep said that a TwoSum set & sub compact should be rolling out soon with the .45 version.