My apologies if this has already been covered. I have several handguns and 223 and 308 rifles. I do not have a tactical shotgun. I am a police firearms instructor and have always used the 870 police model. I love the 870 but have seen that the autos are faster. I am not saying that price is no object but I tend to buy guns on the higher end of the scale. Which shotgun would be best when the feces hit the rotating oscillator?? I am considering the Saiga. 870, Remington 1100 (or is it 1187) tactical and the Benelli M4. I would like feedback from people who own or have shot the above. I am not interested in a brand X just because it cheaper or looks like or functions like the above. Remember the zombies are coming. Thanks.