A benelli super black eagle II is arguably the best waterfowl gun ever made. I have several hunting buddies that have them and love them.
I have a Browning A5 wicked wing 12g that eats everything I put in it. Never had a jam, though I do spray it with ballistol after every hunt, and will take the gun apart if it gets submerged.
I also have a benelli M2 20g that I like a lot. It's only had about 2 boxes of shells through it and but hasn't had a problem.
All guns will fail when dropped in the mud, or without routine cleaning.
I shoot a Benelli SBE1 and a Benelli M1 super 90 for waterfowl. Neither have ever given a moments trouble and even with magnum loads the recoil is soft. I even shot a duck one handed one time with the super 90. If you can't fork out that kind of cash I hear really good things about the Stoeger 3500 shotgun which is very similar to the SBE and Stoeger is owned by Benelli. I think you can get into a Stoeger for under $700.