The fastest current production pump action, based on breaking 7 hand thrown clays, is the 500.
IMHO, that's the expertise of the shooter not the quality of the gun. Do you really think the gun was 'fresh-out-of-the-box' from Big-5? Using that as a reason to buy a gun makes about as much sense as buying a car brand because it's A NSACAR winner.
If you really want to buy a gun based on performance, check out Perazzi's standings at the last Olympics. You can get a gun just like the champs use. Since many "tactical" shotguns either are converted to sporting uses or become closet queens, does if really make a difference between Mossberg or Remington?
Case on point: Many years ago, one of my business partners wanted a HD shotgun. He'd shot some Skeet with one of my O/U and exhibited exceptional hand-eye coordination, so he wasn't a total shotgun newbie. He did a comparison and eventually selected a Mossberg based on price. He shot a few rounds of Skeet with it and assured me that he's shoot it enough to maintain proficiency. I didn't hear anything about the Mossberg for several years. When he was remodeling his home, on a seaside bluff, he taken the neglected Mossberg out of the closet only to find it badly corroded. I tend to think his wasn't a unique case.