[Uncle Ben]

Both are indeniably very good guns, but I bought the mossberg 500 and here's why:

-tang safety is easier to use and see during operation
-slide release is much easier to access, with less finger manuvering/movement needed

For me, these two reasons are enough, but I certainly have nothing against the 870 or anyone who swears by them, cause they have more than proven themselves, but so has the mossberg 500, just not for quite as many years but more than enough to say that it has "stood the test of time"