I have used both shotguns as a prison officer and a deputy sheriff. My own shotgun was a 500, which I much preferred over the 870 for a number of reasons. The 870 should have the loading spoon slotted, as in the heat of a firefight, a shell can end up under the spoon, effectively locking the shotgun up. The slot allows a key to work the shell out of the position. The Mossberg has dual action bars, where the 870 has a single, the safety on the Mossberg is on top of the receiver, basically under the thumb, while the Remington is awkward to operate, being where it is. The idea of the receiver being aluminum is, to me, a non-issue, as I never had my Mossberg fail because of the receiver breaking. Tthe 870 is a respected shotgun, but for my money, I will go with Mossberg. recently on Guns and Gear on the Sports Channel, Mossberg 500 and 590 shotrguns are now available in modular set-up. There are somewhat over 1,000 possible combinations of stocks, magazines, grips, sights, and more.