I have an EKP-8-02. I have heard that the previous models with the other type can fail under recoil (the spring gets too compressed to keep the batteries held securely). The coil cell model doesn't. Mine sits on a Saiga 12 and works just fine.
It works well, I like the variety in reticles, but the batteries are a slightly odd size and while findable, they aren't at Walmart. The body of the optic is rather bulky. The battery doesn't last a super long time and the elevation/windage adjustments aren't as easy to use as those on Aimpoints or EOTechs.
IMO, if you can find one at $300ish, it's a good and worthy optic. If the cost is much above that I'd give it a miss. An Aimpoint PRO can be had for about $350; toss in another $100 for the side mount rail and you've got a better optic. Ditto an EOTech at about $400-500. At Kalinka's $450 for the previous model, I'd probably go with one of the others... not that the Kobra is a bad unit, but that you're going to get something that is not all that common and is not as easy to get service if needed.