A couple quick statements
1. The Holosun mini red dots should seriously be looked at. I have a 507C which I have used on a Glock 17, a Ruger PCC 9mm, and even threw it on a 5.56 AR. I have not experienced any problems with it in a little over 2000 rounds combined on the above weapons. No loss of zer and still using the same battery over several months now.
2. If you can use Duracell batteries do so. I went to the Sage Red Dot Instructors course and he said he has found the most success with that brand. He also said that Duracell batteries are shock isolated batteries. If that's true great if not I wouldn't know. I to have found great success with Duracell batteries.
3. On setting 8 I am getting 41 days on a Renata brand cr1255 in my ACRO. I have shot it on a 17 MOS enough to say its duty rated in my opinion. Just replace the battery monthly. Battery prices have fluctuated on Amazon. I got my ACRO from Stroman pretty early and found out about the Renata batteries early to. I bought a bunch @ .50 so I am pretty good. I would carry the ACRO on duty right now, but the STI Tactical does not have a plate yet for the ACRO. I have talked to a couple places that could mill and retrofit the STI for the ACRO, but currently that juice is not worth the squeeze.
4. If I had to list mini red dots in order of my preference and experience it would be:
Trijicon RMR is the gold standard. I use a type 2 currently, but the 1's are perfectly useable
After that the DPP, ACRO, Holosun 507C are all tied for #2
DPP being at the low end and Vortex being below that.
There is one guy at my PD with a Sig Romeo. I have fired 10-15 rounds with it. Not enough in my opinion to make a comment either way. He is not a shooter so I wouldn't even take his opinion on the matter. Dots on pistols is a 100% voluntary program at my PD. When I mentioned we should probably have some yearly in service for guys choosing to put dots on their pistols I was told a yearly qualification would suffice. I have since offered my program to a local training group that actually pays me (not much, but that wasn't my goal) to teach rich civilians who want to learn the dot.
I have only done two classes, but we got 20 or so students up and running. Im fairly new to the training people game. I started in 2017 at the PD and unless is mandatory training most don't care. Open firearms classes for all the agencies in my area barely get the minimums required.
A local Cop who recently retired has a small training group and has to turn 5-10 people away from his open enrollment classes. He asked me to teach and I said yes. He then told me he would pay me and get me lunch and I was totally surprised.
5. A few months ago I bought a Sig 320 PRO in 9mm. Last year we allowed personally owned pistols for patrol. In that time 6 guys bought Sig 320 pistols to carry. I didn't have a 320 and thought as a FI for my department it might behove me to have some time on one to better train the troops. I use that as my excuse, but I wanted to buy another gun. Anyway the PRO is a newer model and is geared to LE. It comes ready to accept the Sig Romeo and the DPP. I sent the slide to Mark at L&M. He offers a few services for the Sig 320's and he drilled and tapped new holes so now in addition to the two already mentioned optics I can now use a RMR. I have also installed a APEX trigger kit so my initial thought of having a training gun similar to the Officers I train has morphed.
6. I know of one Officer in a different agency using the SRO as a duty optic. He likes it and i'm confident he could still get the job done if it broke and he needed to do work.
Again these are my opinions and may very from yours. Im just passing on information.