I personally would not like the Sporting version of the RBL. I have found later than I should have it is more enjoyable shooting a field style gun at Sporting Clays.
I regularly shoot with a group of elder gentlemen who shoot mostly side by sides. One shoots a 1909 Purdey, one shoots a Purdey hammer gun and one may shoot a Woodward or a Boss.
I occasionally shoot my two English guns as well. Never use the heavy loads but mostly the B&P Comp 1 in 7/8 ounce.
Much more enjoyable to shoot a field style game gun than a supped up sporting clay monster.
Now I would like to add a couple of choices to the list,
Beretta's new 486 in a 30" version. They are getting great reviews over in the Driven shooting world of the UK.
There is also a Winchester Heavy Duck with 30" tubes and much easier to find than a Browning with the same barrels.
Also a real nice sleeper that can be found is the POLI. You can find them with 30" tubes and they were made to shoot clays. The ones I have handled feel GREAT! No ejectors though but who needs them.
All of these can be had for less than a RBL. And will probably be easier to sell at a later date.
Just my thought.

Mike Proctor