I agree with Kimber1911_06238. It's just what you can afford. I love my auto with heavy loads, really tames the recoil. Just as good on ducks as it is on doves. Wish it handled 3" loads, but hey, it works with 2 3/4" stuff pretty decent and I don't do much goose hunting. I wouldn't mind getting a Remington Spartan 453, but it's not that high on the want list. My 3" chambered Mossberg covers the 3" problem just fine. That gun has slain a lot of waterfowl over the last 15+ years and the Mossberg I had before that (just had to have the posh camo) did, too.
I've mostly used my Winchester M1400 on dove the 20 years I've had it, but I'm getting older and less recoil tolerant and that gun fits me like a glove. Lately, I've started using it on waterfowl when boat rides and bays aren't involved. I take care of this gun. sm on the shotgun board turned me on to waxing it with paste wax and so far, it seems to be protecting the wood and metal parts pretty danged well. That camo/plastic Mossberg laughs at salt marshes, though. If they ever offer the Spartan in a camo finish, I'll be wanting it more. I think it's offered with polymer stocks, but I'd like the camo finish, rugged and blends with the vegetation. All reports of the Spartan 453 I've read say it's a good gun and it only runs about 400 bucks, cheap in a world of Benellis, SX3s, and such. A waterfowl gun, IMHO, shouldn't be a show piece, it should simply work.