I have been shooting sporting clays for about 7 years now, and have owned all of the above shotguns.
I agree that the Browning O/U are the better "Browning" guns to shoot...Cost permitting.
Personally, I am a Beretta fan, I have had 2 auto's and currently shoot an O/U...The O/U's are nice, especially in Sporting Clays, because you can have 2 completely different shots in distance, you now have 2 barrels with 2 different choke tubes in them, to pick the best pattern, for the shot.
I have shot with pro's who opted for the Beretta Auto's...Again, whatever works for you.
I agree with Citori...The 11-87 is a darn good gun, reasonably priced. I have seen them used for as little as $375.00-$400.00
The newer "Sporting Versions" of the 11-87 are a little more pricey...
At the time, I had more $$$ then brains...I could afford to buy a new gun each week, until I found the "right" one for me.
Make sure the gun fits you right...No matter what the gun, if it doesn't fit, your scores will suffer.
Hope this helps...
Let us know, what you decided on...