Do NOT buy a Ruger Red Label, especially one of the new ones that are still hanging around in a few places. Ruger had so much trouble with this gun that they have discontinued them AGAIN and forever. They have quit servicing shotguns, even the older ones. The 12 gauge guns were the worst, 20 gauge guns not too bad but there were still quite a few lemons. If you luck onto a 28 gauge RRL in good shape, they are nice guns, but if something goes wrong, it's tough to get them repaired. There are just no parts available. I talked to Briley the other day about my 28 gauge, and even they won't work on it.
For a sub-$1500 budget and new, I would recommend, in this order: SKB590, Weatherby Orion I, or any of the CZs or Yildiz.
http://www.skbshotguns.com/Shotguns/590.phpThe new SKB shotguns, made by Akus in Turkey, are every bit the quality of the older Japanese made SKBs. I have two of their SxS guns and they have quickly become my favorite pheasant and quail guns. x
Also made by Akus, the Weatherby Orion I.
http://www.weatherby.com/products/shotguns/over-under.htmlIf I was in the market for a new O/U in your price range, the SKB and Weatherby would be at the top of my list.
CZs and Yildiz are a step down, but still good guns for the money. I have a CZ Canvasback 12 gauge that has been flawless for sporting clays, and I have a friend who has one with over 30,000 rounds through it without a hiccup. CZ warranty is 5 years and their customer service is perhaps the best in the business. I don't own a Y-gun, but I have handled one - nice gun if a bit light for my taste. Serviced by Briley I believe.
http://cz-usa.com/product-category/shotguns/over-under/If you don't mind going used, then there are tons of possibilities in used Brownings, Berettas, SKBs and others.
I always recommend handling as many different shotguns as you can and get one that fits you the best and feels the best to you.