I've got all 3, Win, Rem, and Mossberg, and I'll take a Rem 870 hands down any day! I sent the Win in for service when it was brand new 3 times, and the issue kept returning, which was that the VR kept falling off.
The Mossberg is an OK SG, but they aren't an 870, never will be. The actions are much stiffer on 500's, and no matter what you do to them, they still have that stiff cheesy feeling action. And if you don't have some minimal experience breaking one down, you'll likely struggle for hours getting one back together. I can't tell you how many people I've had bring me their 500 to show them how to reassemble it. On the other hand, when my boys were in their single digit years, they would have contests breaking down and reassembling 870's blind folded. My youngest, 8 yrs. old at that time, was tearing one down and reassembling in something like 2 minutes, blind folded.
GS