Have shot 3s when I can find them but usually stick to 2s just because they’re more readily available. I’ll shoot 6s at early teal and 4s at wood ducks.
3s were the ballistic big brains' recommendation when steel became the norm. Don't know if that's still the case or not, but I prefer smaller shot, particularly 5s, for all ducks. Perhaps because they still afford enough chances for me to win with the little 7/8oz 20ga loads that have also become my preference.
Wouldn't go out of my way to chase a goose with it, but seems to fit the needs of vast majority of duck situations. With a wide open choke it won't tear up an early season blue wing in close, and choked down a bit provides a fair punch to bigger birds later in season.