I have a Mossberg 464. They are quite tight when you first get them but loosen up very nice after a few hundred rounds. I really dislike the rear sight leaf and had to modify it so it would not shoot 15 inches high at 100 yards using 170gr bullets.
Its an OK rifle for an OK price, other than the iron sight issues, I really haven't used it enough to comment on its life expectancy. I have a run of homelaods going, so I'll soon see how it handles with a bit of extreme use...