I spent endless time last night reviewing, looking, listening to what people had to say about various "red dot" optics. There is end amount of money one can spend on this stuff...so if money is no object ...buy the best. In my case I'm not going to have to depend on these optics for day to day existence, that's of coarse unless the Zombies start taking over.
I looked at everything from Trijicon all model (prefect purchase if I win the lottery) and Aimpoints. There were a couple product that I uncovered flying under the radar, two companies that I current have good experiences with; Vortex Optics and Leathedwood for less money!
Vortex makes two models similar to Aimpoints as does Leatherwood for even less. if you go to Youtube and search on Leatherwood Red Dot and and Vortex Strikefire and Vortex Sparc you'll see reviews and what their owners have to say. I think for us Civi's they will do the job and keep you out of the poor house too.
My plan is to run several hundred rounds of both .223 and 5.56 through it first (i just got my ACR last night)...see what it likes to eat and throw up. Once, that's done, I'll work on getting the most precise zero I can and then work on getting the best groupings at 100 yds. with various weight bullets (factory ammo), and then take it out to 200 yds. And that's where I think I'll stop testing, I will then start reloading to duplicate the best loads. I currently reload 55gr. 223 and 75gr. match ammo. From what I can tell after much reading the ACR like 55 and 62 gr. (actually it will shoot anything) but the 62gr shows much promise. I like to feed it some 62 gr. 5.56 and see how she like it.
Fix sights: MI, Troy, and GG&G are some of the ones I came across. They are not hard to find...just Google "Folding Sights" and you will see the most popular. The key for me if I get a "RED DOT" of any favor is for me to be able to get the red dot right on top of the front post. This might all sound like a royal pain in the ass, but getting and holding zero is what I obsess about.
There is beautiful and deadly scope made by Horus Optics and not too expensive that I would like to get; the model is the "Hawk" they have this amazing reticle H425 that almost guarantees a second hit every single time regardless how far the shot is taken from (and I'm talking 1000yds out). I'll wait to see if and when BM comes out with a 6.8 barrel to see if ACR's are capable of making that shot... if not I'll go ahead and build a snipper rifle. i.e. M24

to go out beyond 300 yds.
There is not limit on how much money you can spend on gear, not to mention the amount of time one has to spend to guarantee reliability and accuracy. I'm just learning from the guy in front of me.