I can't honestly speak on the supernova, I have never shot one, or even handled one. But, I boughta Nova the 1st year they came out, and I have been hunting with it ever since. It is one tough gun...Its been drowned, covered in mud, used as a boat paddle and still killed ducks. I can't recommend a better pump shotgun. the only problems i've ever seen is that the gun is bulky(not heavy, just big) and it doesn't fit some people. play with it and make sure it fits you right.
I was looking into the supernova for a turkey gun, but got a good deal on the 835.