Back when I was younger and tougher, dumber, whatever, I used a 10 gauge Browning BPS for ducks. It was an absolute hammer. I would far rather shoot a 10 gauge than 3.5 12 gauge. The weight of the 10 helps with recoil. Recoil never seemed as sharp with the 10 compared to the 3.5 twelve. On paper, the 3.5" 12 gauge loads would seem to compare equally and even outperform the 10. I have shot both. Hunted with both. There is something about the 10 that gives it noticeably better on game performance. I had a lot fewer cripples when shooting the 10. Mine preferred number 1s or Drylock 1 5/8 oz 2s. Lead 4s for turkeys In a 2 1/4oz load. Perhaps shorter shot string, better patterns, I don't know, but there is some intangible there. That thing would absolutely dishrag ducks.
The biggest issue with the 10 for me nowadays is ammunition cost. Also the titanium plate in my neck makes shooting heavy loads in any gauge painful.