Supers is an emerging company into the bodyboard fin marketplace out of Australia. Burg and Glen Thurston, pro bodyboarders, started the company.
Strikingly similar to Churchills, these fins are an excellent alternative. Everything is basically the same except for a bar from the foot pocket through the blade, adding strength.
It might be hard to decide what fin to get since they are very similar so here is my take on which you should choose.
They are very similar down to the color so it will come down to quality of the material they are made out of. Churchills are now manufactured in China and are softer. I dont recommend this, so I would choose Supers in that case.
This was a recent change in manufactures (full story here) with Churchill. The good material was manufactured in Malaysia and there are still plenty of those Churchills with the good rubber to buy. So in that case I would buy Malaysian Churchill fins (but not Chinese) over Supers fins.
You can find the Malaysian Churchills here if you are shopping around for fins to purchase.