I've been using Mossberg 500 variants for about twenty years and they have never failed me and I've never had a breakage.
I have found that they function more reliably than Remington 870's when both models are mistreated and not maintained at all.
They do have some "rotational slop" on the pump action as some have noted. So what? It affects nothing whatsoever, and the darn things just work, period.
As for those who automaticcally dismiss Mossbergs as being garbage, well, feel free to continue paying more than you have to for less reliable brands if you like. It's your money.