Agreed -- buy a few boxes and find what patterns well.
Other considerations are cost, the size of ducks/geese you want to kill, and average shot distance.
For the OP, 3" steel #1 or #2 would be hard to beat. #2 if you think you'll shoot more ducks, and #1 if you'll shoot more geese.
Point that hasn't been made yet ------ buy ONE SHELL that can handle most of what you do and shoot only that all season. This seems extreme, but you'll get an instinct for how this shell shoots and then hit more ducks. It's a mindscrew to try and shoot multiple types of shells in a short period of time, god forbid one hunt.
DaveinAz has a really smart blog about shotgun reloading (and buying factory shells). He does a lot of writing on steel vs. bismuth for waterfowl and will give you a thorough analysis for making choices.
I like to shoot big ducks over decoys, so realistically I shoot about 80% mallards and some pintail. Usually, I'll get invited on 1-2 cackler hunts a year. For that use case, 3" steel #2 is optimal and steel #1 could work.
On brands, price is a factor but so are other things like:
- How dirty is the shell?
- What color are the hulls? Can you find them easily in the marsh after a hunt?
- Can you buy them reliably year after year?
- Case discounts?
- Is the shot smooth and round or does it look like metal Nerds?
Winchester Dry Lok 3" Steel #2 is a winner. Beautiful quality steel shot and burns very clean. This is worth the extra expense to me. Gotta buy a case from a place like Mack's Prairie Wings or Rogers though.
Kent is solid and budget friendly. You can buy anywhere.
Federal Power Shok (the blue box stuff) is what I'm shooting right now cause I couldn't find more Win Drylok and was on a budget last year since we had a kid. These Federals are the dirtiest, nastiest shell I've used. Unburnt powder sludge in the gun and sometimes in your face! Kills ducks though and is cheap.
If you want to spend a lot on bismuth, the new Boss stuff does hammer ducks. Some of my hunting partners like them. You have to choke it differently though.