Personally I haven't been overly impressed with the 828U, the ones I've been around often had trigger problems that presumably should have been rectified on the newer models.
The "sport" model seems to have several things going for it in that it's got a balancing system so you can tune the forward/rearward balance to the individual users taste. The adjustable stock is a great idea in theory but in reality I can imagine some problems in keeping stock bolts tight when there are shims involved. This hasn't been a problem on semi auto guns but they don't have the same forces on them as an over and under gun being repeatedly opened and closed. They've increased the weight to just over 8 lbs, that's a good thing on a high volume gun. The Stoeger rep that I saw talking about the sport model mentioned that Benelli had solved the wear issue on over and under guns with the floating breech block. I find this statement quite amusing and somewhat offensive, he seems to be completely unaware that other manufacturers solved this problem decades ago with replaceable trunions and locking pins/tongues, not sure where he's been all these years! You can tighten up a 686 quite easily and cheaply but I don't see that happening with an 828U. And you might argue that they won't loosen up but in my experience, anything that moves gets worn out after a while. In my opinion, the floating breech block was the answer to a non-existent problem and I feel it has too many moving parts to ever be a credible gun to the guys who fire tens of thousands or rounds each year.
Personally I don't like the styling of the 828U's, the matt finish is cheap to make because the steel doesn't have to be highly polished and so is popular with manufacturers these days. They've put a nice ten mm wide rib with a tram line on it which is great although I don't care for the carbon fiber. The checkering is wide and looks to be ten or twelve line per inch, this also is easy to mass produce with less labor than 20 LPI, the trouble is that it gives it a cheap look in my opinion but I recognize that these things are all personal taste and not relevant here.
The 828U Sport is not for me but I wouldn't try to talk anyone out of purchasing one if they appeal to you. Try finding out who your local Stoeger rep is and get in contact with him, he may be able to put you in touch with one of the first ones to come ashore!