I've talked to many gunsmiths, and the general concensus is that Mossbergs are underrated. Of 12 gunsmiths I have talked to, the only COMMON complaint is that the safety button loosens and is lost. Outside of that, they have never had one in for major repairs.
I have a 500 and a 590 and they are great shotguns. I had to send my 870 to Scattergun Technologies to have it reworked because it was worn out. Course, it's only 38 years old and had been in a police cruiser exclusively until last year when I bought it...