I am a fanatical duck hunter and call in a duck camp for other hunters. O/U's are reliable and look good but they are a nightmare when used to duck hunt for many. There are a few who like them. They are not good in tight areas like blinds. They get dinged up all to heck in boats and they have a tendency to kick out live shells (The ones built like the Beretta O/U I owned did anyway.) at the most inopportune times when you are wading with them in flooded timber. If you wade in to hunt and stand in water, it is not a question of "if" but "when" you will drop your shotgun in the water. If you duck hunt with any shotgun and think you will not get it scratched up, dirty, muddy and wet, then you are in for some serious discomfort.
I personally run a Browning Gold with wood furniture. I really like the speed load function whereby a live round is automatically kicked into the chamber when the bolt is kicked back after you are out of "bullets". The newest version offering this neat feature handed down from the Auto Five is the Browning Maxus. Plastic stocks and a polymer matte finish are better but I also hunt with a duck call made in 1945-----like the looks of wood furniture. You will need to be completely familiar with a full strip down procedures for any shotgun you seriously duck hunt with or know a good gunsmith and have plenty of money to spend on having it cleaned thoroughly and frequently.
The automatic will malfunction sooner or later I don't care how much you paid for it or who made it. It is just a part of life and the trade off for being able to get off three shots quickly. The O/U will kick more but be reliable to a fault if you keep it clean. Either way you will be well served just go into it with all the facts. The best duck hunting 0/U's for the money are the lower end Brownings and Berettas. The Winchester 101 is also an excellent choice. The Ruger will be brutal on your shoulder. If I ever go back to the O/U, it will the current Belgium-made production Winchester 101 field grade.
This is opinion based from years of experience your views may be different.
Here is what i am talking about----both situations where the shotgun will be abused.