I was running over the same thing with my latest build. I now own 4 ARs, one has an Aimpoint, 1 has a EOTech 512, and 1 has a ...well ok type scope. I was going to upgrade the scope when I started the newest build.
I didnt even know Kobras came with a rail mount till I started looking at them recently.
I have been working with a EKP-8-18 Generation 2 Kobra for several days now. Its mounted on a A2 type Carbine with a ARMS#39. The guy who owns it (the weapon) has put over 4000 rounds through it without any trouble. I have put over 800 in the past few days...(I just tapped out a couple more tonight...
The Kobra is awesome for the price. I see no reason other then purest bullcrud reasons not to put a Kobra on a AR, if you are trying to keep the price down.
Heck, I dropped a Ford 5.0 into a 76 Chevy Nova and nearly had to leave town people were so pissed at me...
Fact is the Kobras are tough battle proven sites. All optics have their bad points, but most people who knock the Kobras are talking about the cheap-0-kobra rebuilds, NOT the latest NIB ones from Tantal.
The Russians are now upgrading their SF units to the new PKAS sites just as our SF units are dumping the Aimpoints for the EOTechs. This is great for guys wanting the Kobras since they will come down in price again...
And if you want a BETTER red dot then an Aimpoint...get a PKAS...LOL. I was checking one out on a AK...blew my Aimpoint away. Mounting it on an AR maybe tricky though.
I borrow a digital camera from someone and post a pic after I get mine...Just to piss-off the AR purest out there...