I've used Cermicoat on a couple of guns. I have been very satisfied with the results. The finish sprays on easily and drys quickly between coats. The finished product looks like black parkerization. It will absorb and hold oil like parkerization also. I cannot really testify as to how durable it is, because none of the guns I've refinished have had any hard use yet.
Since I've done these guns I've found another cermic based flat black bake on finish at Autozone. It is desinged for engine parts, but apears to be essentially the same except you get three times as much in the can for half the price. I have not tried this new one yet.
Good Luck