Last thing you might consider is this is your first shotty, you'll buy others. Maybe spend less now, figure out what you really like and whats important in a firearm. Next gun, get what you really want, after you know what that is.
Unless you decide the sport is not for you, I suspect the bold part of this quote will prove to be true.
When I started migratory bird hunting (40 years ago) I had only a 16 gauge single shot Cooey. My friends had pumps and autos. At the end of every hunt, I noticed that our bags were usually quite similar. The difference was that the others used 3 times as many shells as I did. More often than not, when they missed with the first shot, they missed with the second and third, too.
In the intervening years, I've hunted migratory and upland with every conceivable shot gun design. In a sense, I still prefer singles over pumps and autos, but now I like two singles in one - doubles - either superposed or juxtaposed. Double trigger SXS's for hunting and single trigger U/O's for target competition.
In your case, my recommendation would be that you look for an U/O (my personal preferences don't apply well to you because I don't hunt migratory anymore). Generally speaking, ANY shotgun will do. What we're really discussing is what might be the most versatile. I'm recommending an U/O because:
- they're superior for target shooting in many ways
- they're not bad in a duck blind, although break actions can be a bit unwieldy in a blind at times
- they're also not bad in the uplands, all things considered
CONSIDERATIONS:
1) Barrel length should be long for target shooting and migratory birds, and shorter for the uplands. 30" or more is recommended for targets. 28" (shorter in thicker bush) is most flexible in the uplands. Here, you will certainly have to compromise, depending on which you expect to shoot most.
2) Double triggers are clearly preferable for hunting, but impractical for targets. Here again, you need to make a judgment call.
3) Pistol or semi-pistol grips offer advantages for targets and for migratory. While straight (English-style) stocks enhance double trigger use, they could be sacrificed in the uplands without significant consequences.
4) New guns will almost certainly come with choke tubes (although, interestingly, we are seeing the first glimpses of a nascent resurgence in the popularity of fixed chokes). If the chokes are fixed, Full and Modified would be most suited to all disciplines at once.
5) No matter what the neophytes will tell you, semi-autos are a PITA at target competitions. They're great in the wetlands, but chew through the ammo compared to other designs. They're okay in the uplands.
6) If you don't like U/O's, a pump should be your second choice. Definitely, U/O's will cost more than pumps of similar quality.
7) Decide if you like the confidence you get from an auto safety, or whether you prefer to assume the safety is off, unless you deliberately put it on yourself.
8) Heed the advice of those who talk about fit. Learn the characteristics of a proper mount. Practice proper mounting again and again until you can do it entirely instinctively. Then, with your eyes closed, mount a gun that you are considering. When you open your eyes, you should be looking right down the rib. If not, there's an issue with fit - either drop-at-comb, length of pull, cast, etc. (keep in mind that you'll probably be wearing your hunting jacket or shooting vest when using the gun).
9) Don't fall for the BS notion that heavier loads equals better results. That's a load of crap perpetrated by ammo manufacturers that are just looking to sell more ammo. Pattern your gun. Find out for certain how various loads pattern at shorter and longer ranges, through differing chokes. Test light loads, too, and be amazed by how the results are far better than you expected (you can test long-range killing power by observing penetration through equal stacks of cards).
10) Borrow lots of guns. Easiest way to do this is to ask if you can shoot a few rounds through another chap's gun while at the range. Many shooters will balk at lending out their guns outright, but have no problem with someone shooting their gun in their presence, provided they handle the gun with utmost respect.
11) Don't expect that a single shotgun will satisfy all your needs, if you get bitten by the shooting bug. If you enjoy any of these sports, you'll develop your own preferences and want different tools for different jobs/conditions.
12) NEVER call a gun a "shotty", unless you're ###.