As I see it, the problem with the O/U's costing less than $1,000 new is that the companies that make or import them seem to be in a constant state of fluctuation.
With Browning, Beretta, and SKB/Weatherby, they have been making and selling basically the same O/U shotguns in this country for the past 50 years or longer. Even if you bought one of their guns 30 years ago, the chances are excellent that you'll have no problem whatsoever finding parts and service for their guns.
With the sub $1,000 O/U shotguns, their record is no where near as long. They may sell like hotcakes for a year or two, and then they go out of business and/or stop importing them. Parts may be difficult or even impossible to find. As long as your sub $1,000 shotgun never needs any parts or service, then everything is OK. But if you bought it a few years ago and they are no longer importing them or servicing them here, then a simple broken part can put the gun out of service for good.
That's why I would prefer to spend a little more and at least know that I've got a gun that can be repaired if it needs to be. With some of the cheaper O/U's, it's a crap shoot. If it needs a part or repair in a couple of years, you may find that your "investment" is totally worthless because it won't work and you can't get the parts to fix it.
Buy a good used Browning, Beretta, or SKB/Weatherby and you'll likely have no trouble with it. Even if it should need a repair, the parts and service are readily available. With the "cheapies", you may save on the initial purchase price, but may find that it's worth nothing on the resale market in a couple of years. I understand that they do make good tomato stakes though.