I've only shot Remington 870s since I was 14 so I guess I'd have to say the Remington 870. Having said that, I do like the position of the safety and slide release on the Mossbergs though.
I have a Benelli Supersport which I use for clays and upland birds (very light and little recoil)....I have a SBE II which I use for deer and turkey...a bit more punch with those turkey loads....
First gun I ever bought. An early 80's Remington 1100. Bare bones, I/C, plain barrel. But man....do I love that gun. Took it out for rabbits this year, and can't remember why I bought the Benelli Nova! ( love that gun too!)