As to holsters, Safariland is mandated across the board for all on-duty activities, optic or not. As much as I enjoy other holsters off-duty the Safariland has proven itself exceptional for duty functions over the years. I can tell you that more than one of our officers-including myself-has been saved or assisting in defeating a disarm due to the quality of the Safariland product.
The only deviation allowed is Dets assigned to UC work and they are running Henry Holsters (https://www.henryholstersDOTcom/).
Henry Holsters is local to us and is a great holster company. They make holsters for other manufacturers under contract so their products are well known under other names.
As to 'buy-in' from the officers...every agency has some that don't like whatever gear you give them, doesn't matter what it is or who made it. For those that do buy in we try to give them as much personal latitude as possible when setting up their duty weapon. That does not mean it is a free-for-all and anything goes. Far from it. But we realize that an officers life depends upon the duty weapon and to make them all carry the exact same thing, in the exact same form factor, is not a wise way to go. As to durability, we have had zero problems. The SWAT pistols are the ones that in every agency get the most round count and most of those guys are running an optic. So far they are-I'll have to check on exacts- likely in the 3-5000 range each with zero issues. Even on our other specialty units with a somewhat lessor round count we have had no issues at all, as a result we very much see the pistols as go-to-go.
We, as an agency, have a large number who see the wisdom of personalizing their gear when given the opportunity. Take for instance patrol rifles. While we do not allow personal rifles they are allowed personal uppers off of a select list of manufacturers. As every lower is an M16A1 or M4 registered lower a great many of our guys are running 10.5-11.5-14.5 inch uppers with their choice of lights and Departmentally provided Aimpoints.
Back to pistols again,...the vast majority of our guys buy their duty pistols back when we trade them in. For some it is because it is a ' good deal' for others it is sentimentality and yet others it is because the weapon has been set up, by them, how they want it. I would expect that the MOS guns in one Gen or another are likely to roll on for my agency long after I retire and most likely-unless 40-watt plasma comes about- for the next 20 years plus.