Why are these so prevalent in competition?
I don’t have one, but I see people buying brand new $5000 race guns and putting these on top. What’s the advantage over other company’s products?
Is it just brand loyalty?
I think a lot of it is sticking with what you know. A lot of people also like the large window, interchangeable LED diodes, and widely available 90 degree mounts. Plus, you can get them in flashy race gun colors. 
Avoid looking at what match gays do. It’s just better to ignore them… maybe they’ll go away. :sarcastic:
Used them for years when I was an uninformed gun game participant. They were light, period. Of course, if the cmore was banged hard on something or the gun dropped on the cmore, the fragile lens containment system didn’t hold up too well. This is a gun games only device. Not to be considered for SHTF use.
They’re that fragile? Wow.
They’ll hold up under normal shooting conditions for a long time. Cmore did a good job in designing them for the intended purpose. For a hard use firearm that will be banged around a lot, the lens mounting lends itself to be damaged easily. I’ve knocked lenses out of kilter on barricades.
I have never owned a C more sight, I did consider buying one as a range/hd sight a few years ago, but I picked up something else. I do allot of research before buying anything, I found both good and bad reviews, allot of hear say, and negative feedback from people who never held one of the Cmore sights, and I came to the conclusion for the price, a Primary Arms Micro Red Dot was a better investment at that time. I do plan on buying an aluminum version of the Cmore sight someday just to satisfy my curiosity, they can be found 2nd hand for up to 50% off origional price because they arent in demand. The military has issued these to soldiers over the years, mostly the gooseneck style that are used on A2 recievers, when I was looking for one they were redily availible, and I am sure they can still be found. I can see how the front lense could be damage in a good drop, but I am not on a battlefield, I am not a prepper (nor could I afford to be) I shoot in the woods or at a range, I am not hard on my weapons, and being dissabled I dont think I will make it far when the Zombies come for me. If you are hard on your equipment, take training courses, or might put the Cmore in a position to be damagesd it might not be a good choice, but if you are like me, and arent too rough on your rifle and you are really interested in trying one, I say go for it, look around you might be able to find one pretty cheap. It is really hard to get a idea of weather or not you will like something without getting one to try, I wish there was a store that would offer rental of optics and accessories, much like my favorite fishing supplier Tackle Warehouse has, because not everyone is lucky enough to have a shop close by like I am (Rainier Arms is 2 miles away).
C-More sights were issued? Do you have a link or something that shows that?
I’ve owned a C-More, OKO and Burris FFII. I came to the conclusion that friction lock windage and elevation adjustment setups are far more prone to zero issues than a quality optic with positive click, detent adjustments. I still have the OKO mounted on a .22 pistol for my wife, due to light weight and field of view. Obviously it’s not intended for serious use.
CWDraco mentions it in his post here
http://www.ar15.com/forums/t_3_18/443789_Whatandapos_s_the_deal_with_C_MORE_.html
Colt, Cmore, and the US Army got together and came up with a Colt marked Cmore on a gooseneck mount for the A2 carry handle, the prolem was for some reaon (probably cost) they went with the plastic Cmore, and they didnt hold up very well during hard use. I will search for more info on when they were issued, I want to say early 2000’s, but it was a while ago. I pretty sure they were issued, I have been wrong before, but there was definatley a colaboration between the Army, Colt, and Cmore
I bought one around 2000 and finally mounted it last year. The friction zero is a pain to work with. I have not banged mine around enough discover just how fragile it might be. Given the opportunity, I will replace it with an Aimpoint.