I have an older model KOBRA on my SAR-1 and it has been both reliable and effective. It has 4 reticules and 16 levels of brightness.
This is what the KOBRA looks like on one of my rifles.
This is how it looks on the other one.
I also have an M4 clone that works well on the UTG quad-rail on my Romanian SAR-1. There is no pic of the sight mounted on my rifle but you can see the sight itself at http://www.ar15.com/forums/topic.htm...=620067&page=1
What I like about the newer Russian PKAS is its “state-of-the-art black dot-red dot operation. Under normal daylight conditions, a precise 1 MOA black dot enclosed in a simple elliptical range-finding circle is always visible without the use of the battery. When needed, a flip of the switch activates a 1.5 MOA red dot."
You also mentioned a Weaver mounted version. Below are two styles of the quick release mount for the side-rail of an AK.
The first mount is higher and permits co-witness with the rifle's iron sights. It also has a somewhat longer rail. The second mount sits right over the iron sights and the rail is somewhat shorter than the first one.
Both sit directly over the bore so there is no off-set to the sight.