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I have it and the SN-4. If I were looking for the CQB optimal optic I would go with the SN-4.
My SN-12 is on a flat top M-4 and works just fine. SN-12 is a special purpose optic designed for the USMC, and later offered to the public. It is very rugged and has great field of view.
Here is a picture of SN-4 on M-16 high top. Note stock modification.