Onery ol' curmudgeon that I am, I'll cast a vote for the 870. Not only have I been shooting them since around 1958, but the riot version was the duty shotgun of the Prison System I worked in for 20 years. For ten of those years my duties included firearms instruction. The 870 is one fine weapon as issued, but some excellent after market accessories help turn it into a close range combat weapon of immense effect.
And like that little pink drum beating bunny in the commercials, an 870 just keeps going and going and going....