I'm in the San Francisco Bay Area.
My department and just about every other department I can think of near me (except CHP and SFPD perhaps) authorize pistol optics for use by their officers. I can only think of one department locally that actually issues them and they're issuing. Glock 45 with an RMR Type 2.
Another large department that authorizes PMO's is Phoenix PD in Arizona. I don't know where you are located, but I'm sure if you call around local plenty of departments near you will likely authorize optics. It's becoming the norm.
Whatever pistol we go with in the next few years to replace our current original M&P 9's will have an optic plate; however, I'm not sure we are going to actually issue optics.
"IF" we decided to issue an optic right now I would lean toward either a Holosun 508t or 509t. I love the RMR Type 2, but from an armorer standpoint I can't think of a bigger pain in the ass than having to swap out batteries department wide on an optic I have to unmount/remount every year.