I have been waterfowling with Remington 1100s for coming 54 years from the Gulf Coast, to Manitoba, to the Chesapeake, to Ontario, to Pamlico Sound, around both fresh and salt water. I have never had a problem except when it was one of my really trashy reloads years ago, or brush from a tight blind getting in the action. No it is not as flexible as some newer designs, and no it does not run as clean as some newer designs, but I don't mind a quick 5 minute spray and wipe after shooting so that was never an issue. In that time span over 40 other semi autos have come and gone, but only a very few had reliability issues. I will not own or carry an unreliable gun. I have seen plenty of 1100s and 11-87s malfunction, and I blame the nut on the back of the stock. But, I would not recommend an 1100 unless you like them as much as I do. Just too many other options in a waterfowl gun for a new buyer out there.
Practically any new name brand semi will work if you do minimal cleaning and maintenance. I do not like inertia guns, but if by hard use you mean not cleaning them I would definitely look at them. And I have seen plenty of Benellis, Stoegers, and Franchis have issues, and again I blame that nut on the back of the stock. Every new A5 I have shot had an awful trigger, but I have a friend who loves the square back profile and it works for him. Berettas usually work, the VersaMax has an excellent reputation, the Franchis have most of the benefits of Benelli without the price tag, Fabarm has a good reputation and feels good to me, and of course there is also the 11-87 if you do not need 3-1/2" capability. I have seen enough issues with SuperMags I am a bit leery. I don't know anyone with a Mossberg well enough to comment. Get whichever one you like best, and if you take care of it, it will likely take care of you.